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BULLETIN OF (ory 
THE BRITISH MUSEUM a 
(NATURAL HISTORY) 


GEOLOGY 
VOL. XKV 
1967-1968 


TRUSTEES OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 
LONDON: 1970 


DATES OF PUBLICATION OF THE PARTS 


No. 
No. 
No. 
No. 
No. 
No. 


ANEW A 


26th May 

13th June 
24th November 
12th January 
toth March 
14th May 


PRINTED IN GREAT BRITAIN 
BY ALDEN & MOWBRAY LTD 
AT THE ALDEN PRESS, OXFORD 


1967 
1967 
1967 
1968 
1968 
1968 


CONTENTS 
GEOLOGY VOLUME XV 
The palaeontology and stratigraphy of the lower part of the Upper 
Kimmeridge Clay of Dorset. J.C. W. Cope 


The correlation and trilobite fauna of the Bedinan Formation 
(Ordovician) in south-eastern Turkey. W.T. DEAN 


Burrows and surface traces from the Lower Chalk of southern England. 
W. J. KENNEDY 


A new Tempskya from Kent. M. E. J. CHANDLER 


Colonial Phillipsastraeidae from the Devonian of south-east Devon, 
England. C. T. ScRUTTON 


Some Strophomenacean brachiopods from the British Lower Silurian. 
L. R. M. Cocxs 


Index to Volume XV 


Ys "= 
25 MAY. 1967 


_ BULLETIN OF 
. (NATURAL HISTORY) 
Vol. 15 No. 1 


hag 


LONDON: 1967 


moe PALAEONTOLOGY AND STRATIGRAPHY 
OF tak EOW ERY PART OF THE UPPER 
KVVibRipGE CLAY OF DORSET 


BY 


eu, COPE, | 


Department of Geology, University College, ‘Swansea 


Pp. 1-79; 33 Plates; 12 Text-figures 


BULLETIN OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 
GEOLOGY Vol. 15 No. 1 
LONDON: 1967 


Dae BULLE DEN (On ore BR ia Sis vuUisi WAVE 
(NATURAL HISTORY), instituted im 1949, is 
issued in five series corresponding to the Departments 
of the Museum, and an Historical series. 

Parts will appear at irregular intervals as they become 
veady. Volumes will contain about three or four 
hundred pages, and will not necessarily be completed 
within one calendar year. 

In 1965 a separate supplementary series of longer 
papers was instituted, numbered serially for each 
Department. 

This paper is Vol. 15, No. 1 of the Geological 
(Palaeontological) series. The abbreviated titles of 
periodicals cited follow those of the World List of 
Scientific Periodicals. 


World List abbreviation 
Bull. Br. Mus. nat. Hist. (Geol.). 


© Trustees of the British Museum (Natural History) 1967 


BRU Sa SOw 
THE BRITISH MUSEUM (NATURAL HISTORY) 


Issued 26 May, 1967 Price £4 15s. 


fae PALAEONTOLOGY AND STRATIGRAPHY 
OE LOW ERCP ARI.OF THE: UPPER 
RIMMERTDGE CLAY OF DORSET 


By J. C. W. COPE 


CONTENTS 
Page 
I. INTRODUCTION : : ; : : : é c 4 
Il. THE KIMMERIDGE SECTION : : 5 : : : : 5 
III. THE NON-AMMONITE FAUNA : 9 : : : é : 10 
IV. THE AMMONITE FAUNA. 6 c : : ‘ 3 : II 
(a) INTRODUCTION : : : ‘ : : i II 
(b) SYSTEMATIC DESCRIPTIONS : : j : : : 12 
Genus Gravesia Salfeld 0 é : : : : 12 
Gravesia gigas (Zieten) . : : : : : 12 
G. cf. gravesiana (d’Orbigny) . : : ; : 14 
Genus Pectinatites Buckman F : : c . 14 
Sexual Dimorphism . : : é ; : 15 
Interpretation of Pectinatites . c ° : : 18 
The Origins of Pectinatites j : é : é 22 
Subgenus Arkellites nov. F F ‘ : 24 
Pectinatites (Arkellites) Pyimatie 5a, nov. . : : 2 
P. (A.) cuddlensis sp. nov. 6 é 6 : : 26 
P.(A.) damoni sp. nov. . , : : : > 28 
P. (A.) hudlestoni sp. nov. ‘ é : : 29 
Subgenus Vivgatosphinctoides Neaverson é ‘ : 30 
Pectinatites (Virgatosphinctoides) elegans sp. nov. : 31 
P. (V.) elegans coynigey subsp. nov. . : . ; 33 
P. (V.) scitulus sp. nov. . é : ; : : 34 
P. (V.) decovosus sp. nov. . ; : : : 5 36 
P. (V.) major sp. nov. : : : : : : 37 
P. (V.) clavellisp. nov. . : F : j : 39 
P.(V.) smedmorensis sp. nov. . ; : ; P 41 
P. (V.) laticostatus sp. nov. ; : c : : 43 
P. (V.) grandis (Neaverson) ‘ : : ; 44 
P. (V.) grandis accelevatus subsp. nov. : : F 45 
P. (V.) woodwardi (Neaverson) . : : : : 45 
P. (V.) wheatleyensis (N eaverson) : : ; : 40 
P. (V.) wheatleyensis minor subsp. nov. 6 ; ‘ 47 
P. (V.) wheatleyensis delicatulus (Neaverson) : i 48 
P. (V.) pseudoscruposus (Spath) 5 ; g ‘ 49 
P. (V.) veisiformis sp. nov. ; : : 50 
P. (V.) veisiformis densicostatus eanee nov. : : 53 
P. (V.) abbreviatus sp. nov. : : é ‘ ; 54 
P. (V.) donovani sp. nov. . : é ‘ ; ; 55 
P. (V.) magnimasculus sp. nov. : : E . 56 
P. (V.) encombensis sp. nov. . : : : : 57 


GEOL. 15, I. I 


4 UPPER KIMMERIDGE CLAY OF DORSET 


Page 

Subgenus Pectinatites Buckman . ; : 59 

Pectinatites (Pectinatites) inconsuetus 5. nov. : ‘ 59 

P. (P.) eastlecottensis (Salfeld) . : : . ; 60 

P. (P.) cf. groenlandicus (Spath) : : : : 61 

P. (P.) cornutifey (Buckman) . : : : : 62 

P. (P.) naso (Buckman) . 62 

Genus Pavlovia llovaisky, subgenus Paani Buckman 63 

Pavlovia (Pavavirgatites) cf. pavavirgatus (Buckman) . 63 

V. EVOLUTION OF THE AMMONITES - 6 : c 0 : 64 
VI. THE AMMONITE ZONES : ; E 66 
Pectinatites (Viyeutoupiananies) alewans Zone ; E 66 

P. (V.) scitulus Zone : é : 5 0 j 68 

P. (V.) wheatleyensis Zone : : : : ; 69 

P. (Arkellites) hudlestont Zone . : : 5 : 69 

P. (Pectinatites) pectinatus Zone é : ; ; 70 

VII. CORRELATIONS 0 : : : . : : : : 70 
(a) Great Britain : 0 ? : : ‘ : : 70 

(b) The Boulonnais . . : : : : 72) 

(c) East Greenland (Milne ievadl) : : 5 : ‘ 73 

(d) Southern Germany (Franconia) ; ‘ : : 73 

(e) Russia (Basin of the Ural and Ilek Rivers) : : : 75 

VIII. REFERENCES . F : : a . : : 5 : 76 


SYNOPSTS 


Re-examination of the lower part of the Upper Kimmeridge Clay of the type section at Kim- 
meridge, Dorset, has involved detailed collecting and re-measurement of the succession. The 
ammonite fauna of some 465 ft. of these beds is described. 

The ammonites belong to three subfamilies ; three genera are represented, and descriptions 


are given of three subgenera (one new) ; twenty-eight species (seventeen new) ; and five sub- 
species (four of them new). 


Sexual dimorphism is recognized in one genus, and is believed to be of a unique type. 


A revised zonal scheme is proposed, and correlations are suggested with Northern France, 
Greenland, and other areas of Britain. 


Comparisons are made with the ammonite fauna of other extra-British areas. The fauna of 
the Lower Tithonian rocks of Germany is shown to be quite distinct from that of the Upper 
Kimmeridgian of Britain, such similarities as exist being entirely due to homeomorphy. 


I. INTRODUCTION 


ExIsTInG knowledge of the Upper Kimmeridgian ammonite faunas of Britain is 
very imperfect. The research work which forms the basis of this account is the first 
stage of a planned research project, in the course of which it is proposed to study 
these rocks and their faunas over the whole of Britain. 

The lower Kimmeridgian fauna of Britain is comparatively well known and it was, 
therefore, considered that the best way to carry out this work was to begin at the 
base of the Upper Kimmeridgian (the base of the present Gravesia Zones) and work 
upwards to the Portlandian.! The scope of the first part of the work embraces the 
Gravesia, “ Subplanites”’ and basal Pectinatites Zones of the type-section. 

1 The Middle Kimmeridgian of Arkell (1956: 21) has, as a result of the conclusions presented herein, 


no real standing. It seems most appropriate to have, therefore, two subdivisions of the Kimmeridgian 
Stage, the line between them being drawn at the top ‘of the Aulacostephanus autissiodorensis Zone. 


UPPER KIMMERIDGE CLAY OF DORSET 5 


Prior to 1913 most of the ammonites from the British Upper Kimmeridgian were 
known under the name of Ammonites biplex—a name which embraced practically all 
Upper Jurassic perisphinctid ammonites. 

In 1913 Salfeld identified some of the British Upper Kimmeridgian ammonites 
with Pavlow’s genus Vzirgatites. Neaverson (1925) showed that these ammonites 
were not related to the Russian Volgian forms as Salfeld had supposed. Neaverson’s 
work, valuable though it was, fell far short of monographing the whole ammonite 
fauna from these beds. Neaverson did not undertake comprehensive collecting 
from the type-section in Dorset, which surely must be the basis for zonal subdivision. 
The sequence there is a thick one, and as far as is known, complete. In contrast, 
the sections in the Oxford district, taken by Neaverson as the basis for his zonal 
scheme, are incomplete and very much attenuated. As a result, parts of his zonal 
scheme are unsatisfactory. 

Spath in the early 1930’s made a collection from the Kimmeridge section (now 
housed in the British Museum (Natural History)), and although this was never 
described, references are made to it in several of his papers (e.g. 1935 : 73). He 
identified Neaverson’s genera Allovirgatites and Virgatosphinctoides with his genus 
Subplanites, proposed in 1925 for a group of ammonites occurring in Franconia; 
he later identified other British forms with the Tithonian genus Lithacoceras; and 
as a result, correlations became established between Britain and Germany based on 
these genera. These correlations were followed among others by Arkell (1956), 
and have now become generally accepted. 

The collections from Dorset now to be described, however, establish beyond doubt 
that the British Upper Kimmeridgian and German Tithonian forms are not identical, 
and these previous correlations are thus without real value. 

Many colleagues and friends have been of invaluable assistance in providing helpful 
suggestions and criticisms. I am particularly indebted in this respect to Professor 
D. T. Donovan, Dr. J. H. Callomon, and Dr. A. Zeiss. 

The receipt of a Research Studentship from the former Department of Scientific 
and Industrial Research, a grant from the British Council under the Younger Research 
Workers Interchange Scheme, and financial assistance from the University College 
of Swansea are gratefully acknowledged. 


Il. THE KIMMERIDGE SECTION 


The Kimmeridge Clay is the oldest formation exposed on the Isle of Purbeck. It 
appears as a long strip, approximately six miles in length and usually less than a mile 
wide, in the core of the Purbeck Anticline. To the north the steep escarpment of 
the Portland Stone effectively isolates this relatively low-lying land. The village 
of Kimmeridge is situated in a hollow beneath this escarpment. 

The outcrop of the Kimmeridge Clay on the northern limb of the Purbeck Anticline 
occurs in a military zone extending five miles westwards from Kimmeridge, and is 
for this reason inaccessible. Eastwards from Kimmeridge Bay, however, the section 
is well displayed for over three miles on the southern limb of the anticline. The sea 
erodes at a substantial rate the relatively soft shales which comprise the bulk of the 
succession, but has little effect on the occasional cementstone bands which stretch 


6 UPPER KIMMERIDGE CLAY OF DORSET 


out from the base of the cliffs to form the Kimmeridge Ledges, presenting a con- 
siderable hazard to shipping. 

The cliffs, which are seldom more than 150 ft. in height, are precipitous and crum- 
bling. A constant trickle of shale debris down the cliffs builds up piles of talus 
at their foot. Occasional larger falls bring down large pieces of the cementstone 
bands which litter the shore at the cliff base, and break the force of the waves. It is 
generally only at high spring tides that the sea can reach the foot of the cliffs. 

At the foot of the beach at low tide small ledges or reefs of shale are exposed, and 
these are the only places where fossils can be satisfactorily collected. 

The part of the Kimmeridge section described herein embraces parts of the Kim- 


CLAVELL HEN CUDDLE 
TOWER CLIFF 


GRE 
CEMENTsTone YELLOW Lepge ese 
CLAVELL’S ROPE rae 
HARD HEA 


ROPE LAKE HEAD STONE BAND 


SPUR BELOW FRESHWATER 
SWYRE HEAD STEPS 


FRESHw, 
WHITE BAND sues STONE “BaD 


Fic. 1. Section of the cliffs from the eastern end of Kimmeridge Bay to 
Freshwater Steps. Modified after Arkell 1947 : 75. 


UPPER KIMMERIDGE CLAY OF DORSET 7 


meridge Clay, whose faunas have hitherto been very imperfectly known. The 
lowest horizon from which collections have been made is the cementstone band 
which forms a prominent reef on the foreshore at the western end of Hen Cliff. 
This bed marks, in the Kimmeridge section, the top of the Aulacostephanus autis- 
siodorensis Zone, and therefore forms the junction between the Lower and Upper 
Kimmeridge Clay. The highest horizon studied is some twenty feet above the 
Freshwater Steps Stone Band. It is proposed to describe, at a later date, the highest 
beds of the Kimmeridge Clay, lying above this latter horizon and upwards to the 
Portlandian rocks. 

This section has been re-measured in detail, using direct measurement where pos- 
sible, supplemented by data acquired using an Abney level to measure the thicker 
lithological units, and to fix the position of the shale ledges relative to the nearest 
marker horizon. 

The system of bed numbering used is that of Blake (1875 : 198-199) who was the 
first to make a detailed description of this section. Although Blake numbered his 
beds from the top downwards (thus Bed 1 was the last to be deposited), his bed 
numbers are for the most part well-defined. It was found that Blake’s measurements 
were substantially correct, but there are several quite considerable errors, some 
being perpetuated by Arkell (1947 : 71-72). 

In the description given below, only major lithological units are described. The 
stratigraphical range of a species may be found more accurately by reference to the 
systematic description of the species, or the section on the zonal stratigraphy. 


Blake’s 
Bed 
Number ft. in. 
Pectinatites (Pectinatites) pectinatus Zone 
9 Shales. : ‘ : : : : : 2620 ) 
Pectinatites (Pectinatites) naso, P. (P.) cornutifer, 
Pavlovia (Paravirgatites) paravirgatus, Ostrea bononiae, 
Discina latissima. 
Io Freshwater Steps Stone Band . : : : ce. 3 
II Shales ei: ‘ 5 : : : 5 : =) 29 ) 
Pectinatites (Pectinatites) cornutifer, P. (P.) groenlandi- 
cus, P. (P.) eastlecottensis, P. (P.) inconsuetus, Ostrea 
bononiae, O. solitaria, Protocardia morinica, Discina 
latissima. 
12 pars Middle White Stone Band . . . ‘ ; cee | 6 
12 pars— Shales and mudstones : : 5 F : a 4) 4 
20 pars Pectinatites (Pectinatites) cf. eastlecottensis, P. (? Arkel- 


lites) sp. indet., Ostrea sp. 
20 pars White Stone Band . ; : : : ; s 38 0) 


8 


Blake’s 
Bed 
Number 


20 pars 


26 pars 


26 pars 
26 pars 


26 pars 


26 pars 


26 pars 


27 pars 


27 pars 
27 pars 


UPPER KIMMERIDGE CLAY OF DORSET 


ft. 
Pectinatites (Arkellites) hudlestoni Zone 

Shales, mudstones, hard“ dicey’”’ bands . ; : 51 
Pectinatites (Virgatosphinctoides) encombensis, P. (V.) 
magnimasculus, P. (Arkellites) hudlestoni, Lucina 
miniscula, Pyrotocardia morinica, Ostrea bononiae, 
Discina latissima, Ichthyosaurus sp. 

Basalt Stone Band . : 3 : : : ee 

Inoceramus expansus, Ostrea sp. 

“Dicey’’mudstones_ . : ‘ ; ; F : 

Pectinatites (Virgatosphinctoides) donovam, Inoceramus 
expansus, Parallelodon sp. 

Shales. : 5 : : : : : oul 
Pectinatites (Arkellites) hudlestont, P. (Vuirgato- 
sphinctoides) reisifornus, P. (V.) veisiformis densicos- 
tatus, P. (V.) cf. reistformis, P. (V.) abbreviatus, P. (V.) 
grandis acceleratus, Ostrea bonontae, Ostrea multiformis, 
Ostrea sp., Protocardia sp., Discina latissima. 

Cementstone ; : : é , : , 

Shales. . : ; : : 3 . ee 
Pectinatites (Virgatosphinctoides) reisiformis, Ostrea 
bononiae, Ostrea sp. 

Rope Lake Head Stone Band . : : : ee 


55 


Pectinatites (Virgatosphinctoides) wheatleyensis Zone 


Shales. : ‘ : ; : ‘ : - Aes 
Pectinatites (Virgatosphinctoides) reisiformis, P. (V.) 
wheatleyensis delicatulus, P. spp. indet., Ostrea sp. 

The Blackstone, or Kimmeridge Oil Shale . : ; 2 
Pectinatites (Virgatosphinctoides) wheatleyensis delica- 
tulus, P. spp. indet, Saccocoma sp., Ostrea sp., Discina 
latissima, Lepidotus sp. 

Shales’. ‘ 3 , : ; ‘ : ere 
Pectinatites (Virgatosphinctoides) wheatleyensis, P. (V.) 
wheatleyensis delicatulus, P. (V.) grandis, P. (V.) 
pseudoscruposus, P. (V.) cf. pseudoscruposus, P. (V.) 
laticostatus, P. (V.) woodwardi, Saccocoma sp., Ostrea 
bononiae, Protocardia morinica, Lucina miniscula, 
Discina latissima, Lingula ovalis, Cerithium sp. 

Siltstone . : 2 ; ; : : : 

Shales) 2 ‘ ‘ : : ‘ , : <7 Ae 
Pectinatites (Virgatosphinctordes) laticostatus, P. (V.) 
woodwardt, P. (V.) wheatleyensis, P. (V.) grandis. 


in. 


IO 


Io 


Blake’s 
Bed 
Number 


27 pars 


27 pars 


28-30 


31 


32533 
32 


33 
34 


35 


36 


o/s 
4I pars 


UPPER KIMMERIDGE CLAY OF DORSET 


Siltstone . : A : ‘ , , ; 
Pectinatites (Virgatosphinctoides) laticostatus, Discina 
latissima. 

Shales 5 2 : 5 : . 5 : 
Pectinatites (Virgatosphinctoides) grandis, P. (V.) 
wheatleyensis minor, Ostrea sp. 

“ Dicey ’’ mudstones and shales . : : F 
Pectinatites (Virgatosphinctoides) laticostatus, P. (V.) 
smedmorensis, P. (V.) clavelli, Ostrea bononiae, Proto- 
cardia morinica, Lingula ovalis. 

Grey Ledge Stone Band (Top Ledge of Spath) 


Pectinatites (Virgatosphinctoides) scitulus Zone 


Upper Cattle Ledge Shales 

“ Dicey ’’ mudstones 
Ostrea sp. 

Shales 
Opialaseuns o 

Cattle Ledge Stone Band 
Pectinatites (Virgatosphinctoides) cf. ER 

Lower Cattle Ledge Shales 5 : 
Pectinatites (Virgatosphinctotdes) SHUTS, 2p (A) ck 
scitulus, P. (V.) decorosus, P. (V.) major, P. (V.) cf. 
major, P. (Arkellites) cuddlensis, P. (A.) damont, 
Gravesia cf. gravesiana, Ostrea bononiae, O. multiformis, 
Protocardia morinica, Lucina miniscula, Modiola autis- 
stodorensis, Exogyra virgula, Lingula ovalis, Discina 
latissima, Cerithium sp., Pliosaurus sp., Thrissops sp. 

Yellow Ledge Stone Band . 4 : : : 
Pectinatites (Arkellites) cuddlensts, P. (Virgatosphinc- 
toides) elegans corniger, P. (V.) cf. scitulus. 


Pectinatites (Virgatosphinctoides) elegans Zone 


Hen Cliff Shales ; : 
Pectinatites (Virgatosphinctoides) elegans, P. (V.) elegans 
cormger, P. (V.) major, P. (V.) cf. major, P. (Arkellites) 
cuddlensis, P. (A.) primitivus, P. sp. indet., Gravesia 
gigas, G. cf. gravesiana, Ostrea bonomae, Ostrea multi- 
formis, Ostrea sp., Exogyra virgula, Trigomia pellati, 
Pyrotocardia morinica, Lucina miniscula, Modiola 
autissiodorensis, Lingula ovalis. 


ft. 


45 


51 


69 


in. 


IO 


10 UPPER KIMMERIDGE CLAY OF DORSET 


Blake’s 
Bed 
Number if: in. 
AI pars Cementstone . ; : : 5 , , 2 "2 0) 
41 pars Shale : : ‘ : : : : : Sy Sh 1g) 
Pectinatites (Arkellites) cf. primitivus. 
42 Cementstone . ‘ é 4 8 


Pectinatites (Arkellites) cf. primitivus. 


TOTAL THICKNESS. ; , ‘ : : . 464 6 


Ill. THE NON-AMMONITE FAUNA 


The non-ammonite fauna, although often abundant in terms of individuals, is 
represented by few species. 


VERTEBRATA 


Pisces. Fish remains are common throughout the succession, but consist mainly 
of isolated scales. Fish scales are exceedingly abundant in the Pectinatus Zone. 
Identifiable fish remains include Thrissops sp., and Lepidotus sp. 


ReptTiLiA. Vertebrae and occasionally other bones occur quite commonly. 
The anterior part of a skeleton of Ophthalmosaurus was found 12 ft. above the Cattle 
Ledge Stone Band, and a skull of [chthyosaurus from 12 ft. below the White Stone 
Band. A posterior tooth of a Pliosaur was found 5 ft. above the Yellow Ledge 
Stone Band. 


BRACHIOPODA 


Discina latissima (Sow.) occurs throughout, but is more common above the Black- 
stone Band. 

Lingula ovalis Sow. also ranges through the succession, but appears to reach its 
maximum just above the Yellow Ledge Stone Band. 


ECHINODERMATA 


One species of crinoid (Saccocoma sp.) occurs as isolated pyritized plates. It 
appears to be confined to the Blackstone and the ten feet of shale immediately below. 


MOLLUSCA 


GASTROPODA: Species of Cerithiwm have been found 27 ft. above the Yellow Ledge 
Stone Band, and 3 ft. below the Blackstone; apart from these occurrences no other 
gastropods were recorded. 


BrvaLviA: Bivalves are the most abundant of the non-ammonite fauna. Exogyra 
virgula (Defrance) occurs up to 27 ft. above the Yellow Ledge Stone Band. 

Protocardia morinica (de Loriol) and Lucina miniscula Blake are abundant through- 
out. 


UPPER KIMMERIDGE CLAY OF DORSET II 


Ostrea bononiae Sauvage and O. multiformis Koch & Dunker, commonly occur 
attached to the undersurfaces of ammonite shells. 

Other bivalves include Trigonia pellatt Mun-Chal., Parallelodon sp., Inoceramus 
expansus Blake, Ostrea solitaria Sow., and Modiola autissiodorensis (Cott.) 

Nautiloids and belemnites are absent from the fauna. 


IV. THE AMMONITE FAUNA 
(a) INTRODUCTION 


The state of preservation of the ammonites from the Kimmeridge section leaves 
much to be desired from the point of view of palaeontological investigations. 

The nodule bed in the Rotundum Zone of the Kimmeridge Clay is well known 
as one horizon which yields reasonably well preserved uncrushed ammonites. The 
author has found uncrushed, or relatively uncrushed, specimens at two other hori- 
zons, both of them in the part of the section described herein. One large isolated 
nodule 25 ft. below the Yellow Ledge Stone Band yielded a few pyritized ammonite 
nuclei, none of which are determinable specifically. The other horizon, the roof bed 
of the Blackstone, yields ammonites preserved in solid pyrite, but in which, un- 
fortunately, the septa have been completely pyritized and have become destroyed. 

All the other ammonites from other horizons have suffered crushing to a high 
degree. The ribbing, however, is generally well preserved, and is the basis for 
identification. The suture has almost invariably been completely obliterated. 

Considerable problems have had to be surmounted both in the collection and the 
preparation of these ammonites. Fossils cannot be collected from the cliffs, owing 
to the fissile nature of most of the rock, and the consequent weathering of the shale 
along the bedding. The abundant pyrite has oxidized, and the resulting selenite 
crystals cover the surface of the bedding planes. 

The shale reefs exposed at the base of the beach at low tide are the only places 
where ammonites can be satisfactorily collected. 

At some horizons, because of the very closely-spaced joints in the mudstone bands, 
it is impossible to extract the ammonites. In this case a plaster cast of the ammonite 
impression is made in the field. The detail reproduceable with thinly-mixed plaster 
is excellent, and the casts so obtained are, for most purposes, as satisfactory to 
work with as the actual ammonites from other horizons. 

The ammonites as they are extracted from the rock form most unpromising-looking 
material from the palaeontological point of view, and careful preparation is necessary 
before sufficient detail is visible for any determinative work. 

The rib interspaces are filled with hard shale, and often the whole ammonite is 
encrusted with irregular pyrite aggregates. The lower surface of the ammonite 
(lower surface of the ammonite as it lies in the rock) is very often more or less 
encrusted with oysters which are impossible to remove successfully. 

The crushing of the ammonites has affected most of the original measurements. 
The diameter has been increased by the flattening of the outer whorls; the whorl 
height is similarly affected, whilst the whorl thickness is reduced to about one-eighth 
of the original dimension. The diameter of the umbilicus is, however, relatively 


12 UPPER KIMMERIDGE CLAY OF DORSET 


unchanged. The crushing of the outer whorl has the effect of making the point of 
bifurcation of the ribs appear much lower on the whorl side than it is in reality. 

For purposes of identification and speciation, therefore, the conventional four 
measurements are not given (i.e. diameter, then the other three measurements ex- 
pressed as a percentage of the diameter). Instead the diameter and the umbilical 
diameter only are given. These are both given as measurements since, as mentioned 
above, the diameter has been increased by the crushing. 

Also given, where possible, are the number of primary and secondary ribs on the 
outer whorl, and the number of ribs at various diameters (usually at 5 mm. intervals) 
within the umbilicus. 

In most cases the macroconch of a species is designated as the holotype. Where 
this is not possible (i.e. when the macroconch of a species has not been found, or 
when no well-preserved macroconch has been obtained), the microconch is designated 
as the holotype. 

In cases where the collection of specimens can only be carried out by the making 
of plaster casts in the field, the macroconch casts have, not infrequently, very much 
obscured inner whorls. The reason for this is that the casts are made of the under- 
surface of the ammonites as they lie in the rock, and these under-surfaces are often 
encrusted with oysters. 


(b) SYSTEMATIC DESCRIPTIONS 
Phylum MoLiusca 
Class CEPHALOPODA 
Sub-class AMMONOIDEA 
Order AMMONITIDA 
Superfamily PERISPHINCTACEAE 
Family PERISPHINCTIDAE 
Sub-family AULACOSTEPHANINAE Spath 1924 


Genus GRAVESIA Salfeld 1913 


Type species by subsequent designation (Roman 1938): Ammonites gravesianus 
d’Orbigny 1850. 


Gravesia gigas (Zieten) 
(Bis re te: a) 


1830 Ammonites gigas Zieten, pl. 13, fig. I. 
1963 Gvravesia gigas (Zieten) ; Hahn: 97, pl. 9, pl. 10, figs. 1, 2 (see also for earlier references). 


MATERIAL. Two specimens. 
STRATIGRAPHICAL RANGE. 40-45 ft. below the Yellow Ledge Stone Band. 


DESCRIPTION. These two specimens, which are similar to one another, are 
crushed flat. Diameter 308-322 mm. Diameter of umbilicus 104-114 mm. The 


UPPER KIMMERIDGE CLAY OF DORSET 


RIB DIRECTION 


— ~— ae 
RURSIRADIATE RECTIRADIATE PRORSIRADIATE 
RIB WIRE 


SECONDARY INTERCALATORY 


== 
BIFURCATE SIMPLE 


POLY GYRATE POLY PLOKE VIRGATOTOME 


Fic. 2. Rib directions and rib types occurring in the ammonites of the 
Upper Kimmeridge Clay. 


14 UPPER KIMMERIDGE CLAY OF DORSET 


original diameter was probably around 240 mm. There is a very close resemblance 
to the neotype (Hahn 1963, pl. 9, fig. 1), the only discernible difference being that 
the Dorset specimens still have quite prominent secondary ribs on the venter at the 
aperture. 

REMARKS. This species is extremely rare in Dorset, two other specimens exist in 
the collections of Spath in the British Museum and are also from the same horizon. 
Salfeld recorded “‘ numerous examples” of G. gravesiana from about this horizon 
(Arkell 1933 : 440). This species appears, however, to occur higher in the succession. 


Gravesia cf. gravesiana (d’Orbigny) 


(Bi tie. 2) 
1850 Ammonites gravesianus d’Orbigny : 559, pl. 219, figs. 1, 2. 
1963 Gyvavesia gravesiana (d’Orbigny) ; Hahn: 99, pl. 10, figs. 3, 4; pl. 12, figs. 3, 4; pl. 13, 
fig. 2. (See also for earlier references.) 
MATERIAL. Two specimens. 


STRATIGRAPHICAL RANGE. From 8 ft. below to 6 ft. above the Yellow Ledge 
Stone Band. 


DeEscrIPTION. Both the specimens are whorl fragments. The larger (PI. 1, fig. 2) 
shows the ribbing very well and is very close to G. gravesiana. The total estimated 
crushed diameter of this specimen would be about 160 mm. 

The other specimen shows only three primary ribs, with internal moulds of the 
secondary ribs, but is similar in rib style to the first specimen. 


REMARKS. Salfeld recorded Gravesia irius at about this horizon, a species which 
the author was not able to find. 

The occurrence of Gravesia above the Yellow Ledge Stone Band has not hitherto 
been reported, but as this genus is so rare in Dorset it is by no means certain that 
the newly established range of 60 feet in Dorset is the maximum range of this genus. 


Subfamily VIRGATOSPHINCTINAE Spath 1923 


Genus PECTINATITES Buckman 1922 
Type species Ammonites pectinatus Phillips 1871. 


DiacGnosis. Dimorphic. Microconchs generally 65-IrI0 mm. in diameter, 
occasionally larger. Inner whorls with sharp biplicate ribbing, becoming a little 
coarser on body-chamber with occasional simple and trifurcate ribs. Peristome 
with ventral horn. Body-chamber generally half a whorl long. Macroconchs 
generally 140-200 mm. occasionally larger, very rarely smaller. Inner whorls 
with sharp biplicate ribbing. Outer whorl very variable, usually with strong primary 
ribs and two to five secondary ribs to each primary rib. Peristome simple. Body- 
chamber generally half a whorl long. Constrictions present in some species. 

Upper Kimmeridgian. (Elegans to Pectinatus Zones). 


UPPER KIMMERIDGE CLAY OF DORSET 15 


Sexual Dimorphism 


Detailed collecting from the Upper Kimmeridge Clay at the type-section at 
Kimmeridge, Dorset, has revealed many ammonites referable to species of the 
genus Pectinatites Buckman. Random sampling has established that the vast 
majority of these fall into one of two size groups. Formerly it has been considered 
by those who had collected ammonites from this section (e.g. Arkell & Spath), that 
the smaller specimens were merely young forms of the larger. However, these 
previous collections consist mostly of individuals from which the peristome had been 
broken during extraction from the rock, and examination of recent collections, 
consisting mainly of individuals with peristome intact, suggests a new interpretation 
of the size grouping. This interpretation arises from the fact that at every horizon 
from which collections were made, only two size groups are found. The smaller 
size falls into the 65-110 mm. diameter range, and the larger into the 140-200 mm. 
diameter range. If the ammonites of the smaller size group were the young of the 
larger ones it would be remarkable not to find, at some horizon, ammonites falling 
into the size range 110-140 mm. diameter. Evidence to show that the two groups 
are quite distinct follows below. 

Callomon (1963 : 25) has summarized the criteria by which an ammonite may be 
judged to be mature. These are: 


(a) Uncoiling of the umbilical seam. 

(b) Modification of sculpture near the peristome; usually a coarsening 
and re- or degeneration of ribbing, but often with terminal constric- 
tions, ventral collars, flares, horns, rostra, lateral lappets etc. 

(c) Approximation and degeneration of the last few septal sutures. 


As the ammonites are badly crushed, all traces of the septa have been destroyed. 
If, however, the first two of these criteria are applied, it is found that both size groups 
mentioned above consist of mature individuals. 

Species of these perisphinctid ammonites are best distinguished from one another 
by the density of the ribbing. If the numbers of ribs at given diameters are plotted 
against diameters on a graph, a curve is produced which is distinctive for any given 
species. The two size groups under consideration here give generally similar, but 
not identical curves, so that it is possible to distinguish, by means of rib curves, the 
larger from the smaller type, even with incomplete material. These two groups 
have been referred to as microconchs and macroconchs by Callomon (1957 : 62), a 
terminology which has become generally accepted. 

The microconchs, in this case, are generally small forms with a diameter of 65-110 
mm., but at one horizon they range up to 185 mm. in size. In all cases the ribbing 
is of normal perisphinctid biplicate style and, apart from slight coarsening towards 
the aperture and occasional development of polygyrate ribs, shows little modification. 
The aperture bears a horn-like process projecting from the venter. The umbilical 
seam gradually uncoils over the last half whorl, so that at the aperture many forms 
are completely evolute. The apertural margin is sometimes devoid of ribbing and 
shows a smooth zone, ornamented little, save for growth lines, and the presence of 
the ventral horn. 


16 UPPER KIMMERIDGE CLAY OF DORSET 


The macroconchs are usually 140-200 mm. in diameter, but occasionally are larger, 
or very rarely smaller, and are characterized by a smooth sinuous peristome margin. 
The ribbing on the inner whorls is of a simple biplicate style, but the point of bifurca- 
tion usually occurs slightly higher on the whorl side than it does on the microconchs. 
The body-chamber develops irregular ribbing and, particularly in the forms from 
higher horizons, has a tendency to fasciculation or virgatotomy. Uncoiling of the 
umbilical seam occurs only over the last half whorl. 

The two forms are found in association throughout the succession, although the 
ratio of microconchs to macroconchs varies. This ratio is usually within the limits 
2:1-1:2. Where only a few specimens have been obtained from one horizon 
this ratio is not treated as significant. 

That these two groups of ammonites are very closely related is strongly suggested 
by their co-existence at each fossiliferous horizon, their identical stratigraphical 
range, and their similar rib curves. However, four specimens from one horizon 
(13 feet above the Rope Lake Head Stone Band) from which have been collected 
32 microconchs and 34 macroconchs, show conclusively the relationship. Three of 
these specimens appear to be normal macroconchs, but have on their inner whorls 
structures resembling those of the horn of the microconch. However, this structure 
differs from the true microconch horn; it has negligible ventral projection, it is 
developed from a single rib, and it projects laterally. 

The fourth of these specimens is unique in that it is intermediate in size between 
the two groups (117 mm. diameter), has the typical microconch horn developed, 
but shows the beginnings of the macroconch type of ribbing associated with four 
further horns. The rib density of the first three of the ammonites shows them to 
have affinity with the macroconch group. The fourth specimen has a rib density 
intermediate between that of a microconch and a macroconch. 

The undersides of the ammonites, as they lie in the rock, are quite often encrusted 
with oysters, although the upper surface is generally free of them. It would, there- 
fore, seem that the oysters attached themselves to the ammonite conch after the 
death of the latter, otherwise the oysters would presumably be equally common on 
both surfaces. They apparently grew in the shelter provided by the umbilical space 
beneath the ammonite, and flourished there until continued sedimentation eventually 
killed them. Medcof (1955) has shown that modern oyster larvae prefer to settle on 
under-surfaces. In this case the ammonite shells would provide the only such 
surfaces available on the sea bed. 

Judging by the size of these oysters, a considerable time must have elapsed before 
they were killed by the continued influx of sediment, so that we may reasonably 
conclude that sedimentation was not rapid. This is also supported by lithological 
evidence. The rocks are a fairly uniform argillaceous series—grey and black shales 
and clays with occasional cementstone bands—and, apart from lamination, are 
devoid of sedimentary structures. 

Save for the very occasional juvenile forms and occasional gerontic forms, all the 
ammonites fall into one of the two size groups mentioned previously, and bearing in 
mind the evidence of slow deposition, it is likely that the ammonite faunas of the 
Upper Kimmeridge Clay in Dorset represent a death assemblage. 


UPPER KIMMERIDGE CLAY OF DORSET 17 


Taking into account the evidence of maturity of the ammonites, and the fact 
that they represent death assemblages, it would appear evident that the difference 
in size of the two groups is of a fundamental nature. It seems most unlikely that 
current sorting of the shells, or sudden extermination of whole populations occurred. 
The most obvious interpretation of this size distribution is that these ammonites 
exhibit dimorphism. Dimorphism of ammonite shells is probably an expression of 
some difference which was present in the soft parts also. The most obvious differ- 
ence between dimorphs would appear to be a sexual one, and there is some evidence 
to suggest that the microconch and macroconch may represent the two sexes. 

Examination of the microconchs yields several important facts relating to the horn. 
It is never developed until a diameter of at least 60 mm. (generally more) is attained. 
In other words, the horn is not developed until a certain stage of growth is reached. 
At various growth stages beyond this diameter further horns may be developed, but 
the presence of a former horn or horns is always detectable. Sometimes the earlier 
horn is retained, and in other cases the earlier horns appear to have been shed, and to 
have left behind a characteristic scar on the venter. 

Apart from the four macroconch specimens mentioned earlier, none shows any 
trace on the earlier whorls of any type of horn or ventral scar. 

In section, the microconch horn is U-shaped, opening forwards. This suggests 
that it housed some part of the soft parts of the animal, and, since the horn is confined 
to the microconch, it is reasonable to assume that its function may have been sexual. 
This would explain its confinement to the microconch, and its occurrence only in 
nearly full-grown specimens. 

The four specimens showing characteristics of each group can then be explained as 
various degrees of intersexual specimens. Three of them are barely distinguishable 
from true macroconchs, but the fourth appears to be a true intersex. 

As mentioned above, the macroconchs and microconchs differ somewhat in the 
density of their ribbing. At 15 mm. diameter (the smallest diameter at which it is 
practicable to count the ribs accurately) the macroconchs are nearly always finer 
ribbed than the corresponding microconchs. The comparative density of the ribbing 
of the two forms, at greater diameters, is seen to vary with the species concerned. 
Presumably, both microconch and macroconch reached maturity at the same age, 
so that the rate of growth of the macroconch must have been greater than that of 
the microconch. This would appear to explain these discrepancies, since growth 
rate in each species must, to perhaps a small and varying extent, have had an effect 
on the density of the ribbing. 

Our knowledge of the soft parts of ammonites is almost entirely based on analogy 
with modern cephalopods, particularly Nautilus. In most living cephalopods the 
male of the species is smaller than the female. In Nawtilus, however, the male is 
slightly broader-shelled than the female, the extra breadth of the shell being utilised 
to incorporate the male copulatory organs, the diameter of the two shells is approxi- 
mately equal. It appears, therefore, that in any case of marked dimorphism in 
modern cephalopods the male is the smaller sex, and it therefore appears likely that in 
Pectinatites the microconch represents the male of the species. If this were so, the 
horn may have assisted in copulation. If the spadix (the copulatory organ of the 


GEOL. 15, I. 2 


18 UPPER KIMMERIDGE CLAY OF DORSET 


male cephalopods) were housed within the horn, by insertion of the horn within the 
venter of the female shell, fertilization of the ova would be more readily assured. 

Dimorphism has been reported in other groups of ammonites by various authors 
(e.g. Callomon 1963, Makowski 1962, Westermann 1964). In many of the reported 
instances, the microconch aperture bears a pair of lappets developed laterally. 
Lappets are not present in any ammonites found hitherto from the Upper Kim- 
meridge Clay, while the horn of the Kimmeridgian microconchs is apparently unique 
to this group of ammonites. These horned Kimmeridgian forms are known outside 
Britain from Northern France and Greenland, and, as they appear to have evolved 
rapidly, promise much in precise correlations within this Upper Jurassic faunal 
province. 


Interpretation of PECTINATITES 


The genus Pectinatites was originally proposed for a few closely related species 
from the Pectinatus Zone of Oxfordshire. The Pectinatus Zone there is to be 
correlated with the rocks between the White Stone Band, and the base of the Pavlovia 
votunda Zone in the Dorset succession. 

As early as 1896 Hudleston (1896 : 322) had remarked on the similarity between 
Ammomites pectinatus and the pyritized ammonites which occur at the top of the 
Kimmeridge Oil Shale or Blackstone, about 150 ft. below the White Stone Band in 
the Kimmeridge section. 

Buckman, in June 1925, assigned one species of these pyritized ammonites from 
the Blackstone to a new genus, Pectiniformites which he placed six hemerae earlier 
than his Pectinatus hemera, but Neaverson (Dec. 1925) did not accept Buckman’s 
findings, and placed these Blackstone ammonites in the genus Pectinatites. Spath 
(r936 : 18) in turn placed them in his genus Subplanites proposed in 1925. 

Herein, I place these ammonites in the genus Pectinatites, in which I recognize 
three subgenera: Pectinatites (sensu stricto); Virgatosphinctoides; and Arkellites 
subgen. nov. 

Many generic attributions have been given to species of Pectinatites in the past. 
These generic names, for the most part, belong to quite distinct genera many of 
which do not occur in Britain, while others of them are either junior synonyms, or in 
some cases subgenera of Pectimatites. As much confusion, and many unreliable 
correlations have been made on the basis of misidentification of species of Pectinatites 
with other genera, there follows a discussion of these genera and their relationship, 
if any, to Pectinatites. 


VIRGATITES Pavlow 1892 


TYPE SPECIES. Ammonites virgatus von Buch 1832. (Subsequently designated 
Douvillé 1970.) 

This genus was recorded from the horizon of the Kimmeridge oil-shale by Salfeld 
(1913), and 2 zone of V. miatschkovensis introduced by him for the beds between the 
Gravesia zones and his zone of Perisphinctes pallasianus (= modern Pectinatus Zone). 
The genus is characterized by virgatotome ribbing on the inner whorls, sometimes 


UPPER KIMMERIDGE CLAY OF DORSET 19 


reverting to simple or bifurcate ribbing on the body-chamber. All the Dorset 
ammonites from this part of the Kimmeridge Clay have normal perisphinctid 
bifurcate ribs on their inner whorls, and it is only on the outer whorl that virgatotome 
ribbing may develop. There is now no doubt that Virgatites is much younger in 
age than these Kimmeridge forms, and appears to be restricted to the Volgian faunal 
province of eastern Europe. 


PSEUDOVIRGATITES Vetters 1905 


TYPE SPECIES. Ammonites scruposus Oppel in Zittel 1868. 

Lamplugh, Kitchin & Pringle (1923 : 222) recorded the occurrence of the genus 
Pseudovirgatites from Dorset, and introduced a zone of Pseudovirgatites to include the 
horizon of the Blackstone in Dorset. This genus is often homeomorphic with the 
genus Pectinatites. The type species from the Lower Tithonian has similar rib-style 
on its outer whorl to that of some large species of Pectinatites (e.g. P. (Virgatosphinc- 
toides) pseudoscruposus (Spath)). Other species of Pseudovirgatites, such as some 
of those recently figured by Donze & Enay (1961) and Michailov (1964), are remark- 
ably homeomorphic with some species of Pectinatites (e.g. P. (P.) inconsuetus sp. nov. 
See p. 138, Pl. 30). The microconch of Pseudovirgatites does not, however, possess a 
ventral peristomal horn as does Pectinatites, and all records of Pseudovirgatites from 
Britain would appear to refer to homeomorphic forms of Pectinatites. 


LITHACOCERAS Hyatt 1900 


TYPE SPECIES. Ammonites ulmensis Oppel 1863. 

The inner whorls of Lithacoceras generally bear fine bifurcate ribs which modify 
on the outer whorl of the macroconch to produce in the type-species widely-spaced 
blunt primary ribs, each giving rise to up to eight secondaries. Some species of the 
genus reach a very large size. There is often a considerable degree of homeomorphy 
between species of this genus and species of Pectinatites. Apart from peristomal 
differences, the microconchs of the two genera can be very similar, and the middle 
whorls of a macroconch of Lithacoceras sometimes very closely approach the ornament 
of the macroconch of Pectinatites. This homeomorphy has misled many workers in 
the past. In particular the species of Pectinatites from the Hen Cliff Shales have 
been identified in the past as Lithacoceras. (e.g. Arkell 1956 : 2r). 


PECTINATITES Buckman 1922 


TYPE SPECIES. Ammonites pectinatus Phillips 1871. 

The name Pectinatites is the most senior available name for the British Upper 
Kimmeridgian ammonites described herein. It is distinguished from all other genera 
which are to varying degrees homeomorphic with it, by its type of dimorphism. As 
these ammonites with horned microconchs form a closely related natural group, it is 
here proposed to include all such dimorphic forms in this genus. 


20 UPPER KIMMERIDGE CLAY OF DORSET 
WHEATLEYITES Buckman 1923 


TypE SPECIES. Wheatleyites tricostulatus Buckman 1923. 

This genus is characterized by finely-ribbed inner whorls, which modify to produce 
an outer whorl with coarse widely-spaced primary ribs; the secondary ribs gradually 
fade on the body-chamber. Some forms of Wheatleyites are homeomorphic with 
species of the Tithonian genus Pseudovirgatites. Wheatleyites is here regarded as a 
junior synonym of Pectinatites, it being a name applied by Buckman to macroconchs 
of Pectinatites having this particular type of modification of the ribs on the outer 
whorls. 


SUBPLANITES Spath 1925 (January) 


TyPEs SPECIES. Virgatosphinctes reist Schneid 1914. 

To this genus belong a complex of forms occurring in the Tithonian rocks of Europe. 
Characteristically their inner whorls bear fine bifurcate ribs, which are modified on 
the body-chamber in a fashion similar to that which obtains in many species of 
Pectinatites. It was for this reason that many of the British species of Pectinatites 
were long considered to be species of Subplanites. Vuirgatosphinctoides Neaverson 
(here treated as a subgenus of Pectinatites), was considered a junior synonym of 
Subplanites. This undetected homeomorphy led to the establishment of a number of 
unreliable correlations between Britain and Southern Europe. 

The microconchs of Subplanites bear lappets, and are for this reason easily dis- 
tinguishable from the microconchs of Pectinatites when material with intact peristomes 
is available, but in the absence of specimens with peristomes it 1s virtually impossible 
to distinguish the two genera. 

All the British forms appear to belong to Pectinatites, but in the case of such faunas 
as those from Russia, recently described by Michailov (1964), it is not possible to 
determine the genus of ammonites present owing to the incomplete nature of the 
material. 


PECTINIFORMITES Buckman 1925 (June) 


TYPE SPECIES (by monotypy). Pectiniformites bivius Buckman 1925. 

The holotype which is in the Dorset County Museum, Dorchester, is a pyritic 
cast from the Blackstone. The pyrite of the outer whorl has in places reached an ad- 
vanced state of decomposition, and the specimen is now of little value. There is also 
in this museum, however, a cast of the holotype made in 1925, which appears to 
correspond very closely in dimensions to the holotype, and which is a better specimen 
than the holotype in its present condition. 

Buckman marked on his plate of the holotype (1925, pl. 568) the position of the 
last visible suture, which is just one whorl back from the supposed peristome. 
However, the type of preservation in the Blackstone (solid pyrite) generally destroys 
all trace of the septa, and in the author’s opinion, the septum marked by Buckman 
was the last viszble, but not the last occurring septum. This view is supported by 
the occurrence of better-preserved ammonites having affinities with this species 


UPPER KIMMERIDGE CLAY OF DORSET 21 


and with a short body-chamber. (E.g. Pectinatites pectinatus (Phillips) Buckman 
1922, pl. 354B, which shows five-eighths of a whorl of body-chamber; and the length 
of the body-chamber estimated from differences in the degree of crushing of the 
Dorset material, which suggests a body-chamber length of between three and five- 
eighths of a whorl. No specimen of Pectinatites is known to the author with a body- 
chamber as much as one whorl in length). 

The ammonites from the Blackstone are largely uncrushed, but there is another, 
more important, difference between the ammonites from this horizon and other 
horizons in the Dorset succession. In the Blackstone, ammonites of all growth 
stages are preserved, from very small nuclei to specimens over 150 mm. in diameter. 
This contrasts with other horizons where mature individuals make up by far the 
greater part of the ammonite fauna. Furthermore, no ammonites have been 
collected (or preserved?) in the Blackstone with intact peristomes. This means that 
it is not possible, in the case of the smaller specimens, to distinguish macroconchs 
from microconchs, and thus that the interpretation of Pectininformites is open to 
doubt. 

Further, the Blackstone has hitherto failed to yield macroconchs with well- 
preserved inner worls, so that the holotype of Pectiniformites bivius cannot be com- 
pared to any known macroconch specimen. It is, therefore, not possible to determine 
to which subgenus of Pectinatites this species belongs. The rib density is such that 
affinity with Arkellites subgen. nov. is unlikely (approximately 55 ribs at 30 mm. 
diameter). It may possibly therefore be consubgeneric with Virgatosphinctoides, 
but there appears to be no over-riding reason why it should not equally be placed in 
Pectinatites, sensu stricto. This was also the view of Neaverson (1925 : 15) ‘‘ Buckman 
has recently instituted a new genus Pectiniformutes for ammonites of the pectinatus- 
type from this facies (the oil shales of Kimmeridge). There seems to be no justifica- 
tion for this, and Pectinzformites must be regarded as synonymous with Pectinatites ’’. 

Pectiniformites would thus become a junior synonym of Pectinatites, and is so treated 
here. 


KERATINITES Buckman 1925 (October) 


TYPE SPECIES. Keratinites keratophorus Buckman 1925. 

This genus was introduced by Buckman for ammonites from the Pectinatus Zone 
having a peristome bearing a ventral horn. These forms are the microconchs 
of Pectinatites, and the name Keratinites is here regarded as a junior synonym of 
Pectinatites. 


VIRGATOSPHINCTOIDES Neaverson 1925 (December) : Ir 


TYPE SPECIES. Vuirgatosphinctoides wheatleyensis Neaverson 1925. 

This genus is characterized by finely ribbed inner whorls which are modified on 
the body-chamber of the macroconch, often producing polygyrate, polyploke, or 
virgatotome ribbing. The genus was regarded by Spath as synonymous with, or 
at the most subgenerically different from, his genus Subplanites proposed a few months 
earlier (see above). Systematic collections from Dorset have now established that 


22 UPPER KIMMERIDGE CEAY OF DORSET 


Virgatosphinctoides is dimorphic. The microconchs bear a ventral horn and are 
never seen to have lappets. Virgatosphinctoides is thus easily distinguished from 
Subplanites when material with intact peristomes is available. The presence of a 
horned peristome, however, shows that Virgatosphinctoides is closely related to 
Pectinatites. The microconchs of the two are sometimes indistinguishable, and only 
the characters of the macroconchs can usefully separate the two forms. For this 
reason Virgatosphinctoides is here treated as a subgenus of Pectinatites. 


ALLOVIRGATITES Neaverson 1925 (December) : 29 


TYPE SPECIES. Allovirgatites woodward: Neaverson 1925. 

Neaverson’s basis for distinction between Virgatosphinctoides and Allovirgatites 
appears to have been based almost entirely on differences in the septal suture of 
species of the two genera. However, the rib-style and its development is very similar 
in these two forms, and there appears to be little justification for drawing distinction 
between them. Neaverson admitted similarity between the suture lines of these 
two genera in the young stages, and there would seem little doubt that differences 
between his described forms are no more than specific differences. Allovirgatites 
is therefore here regarded as a junior synonym of Virgatosphinctoides. 


SUBDICHOTOMOCERAS Spath 1925 (January) 


TYPE SPECIES. Subdichotomoceras lamplught Spath 1925. 

This genus is characterized by sharply biplicate ribbing throughout development, 
together with deep constrictions which are bordered by simple ribs. The aperture 
is without lappets. The holotype came from the Eudoxus Zone of Yorkshire, and 
the genus does not appear to be represented in higher Kimmeridgian deposits in 
Dorset. 


SPHINCTOCERAS Neaverson 1925 (December) 


TYPE SPECIES. Sphinctoceras crassum Neaverson 1925. 

Two species of Sp/inctoceras were described by Neaverson from the Wheatleyensis 
Zone of Oxfordshire. They are massive inflated forms with coarse strong biplicate 
ribs. There seems little doubt that SAhinctoceras is closely related to Subdichoto- 
moceras, the former being almost certainly the macroconch of the latter. No 
specimens of Sphinctoceras have hitherto been found in Dorset, but the genus is 
mentioned here because the conservative “‘ biplex ’’ stock to which it belongs gave 
rise to the pavlovids in the Pectinatus Zone. The sharp biplicate ribbing, the very 
high point of bifurcation of the ribs, and the absence of polygyrate ribs and any 
marked apertural modification make identification of these forms with more coarsely- 
ribbed species of Pectinatites unlikely. 


The origins of PECTINATITES 


The origins of Pectinatites are rather obscure, but there is one feature of the ribbing 
which must be considered of great value in deducing the origin of the genus, This 


UPPER KIMMERIDGE CLAY OF DORSET 23 


is the presence of the polygyrate, and more rarely the polyploke rib type (Geyer 
rg6r, text-fig. 1). This type of ribbing, which is first found in some Upper Oxfordian 
ammonites, is the first new character in perisphinctid ornamentation to appear since 
the Bajocian, and it therefore appears very probable that all ammonites which have 
this rib style are related. 

In the Lower Kimmeridgian genus Ataxioceras, the development of polygyrate 
ribbing reaches its extreme. Ataxioceras is also often ribbed in a most irregular 
fashion, a character which is evident in many species of Pectinatites. A further 
character of Ataxioceras is of importance too in tracing the origin of Pectinatites. 
This is the apertural modification of the microconch. Most microconchs of Ataxtio- 
cevas appear to have well-developed lappets (e.g. Geyer 19614, pl. 14, fig. 2), but there 
are specimens which appear to have a horn developed (e.g. Geyer 19614, pl. 13, fig. 5). 
It thus appears that three of the most important characters of Pectinatites are also 
found in Ataxioceras. 

There must also be taken into account the remarkable similarity of some species 
of Pectinatites to species of the Tithonian genera Subplanites, Lithacoceras, and 
Pseudovirgatites. There can be no doubt that there was a marine connection between 
Britain and the Swabia—Franconia area at least for a short while after the Lower 
Kimmeridgian, since the genus Gvavesia is common to both areas. However, there 
are apparently no substantiated records of Lithacoceras or Subplanites from the 
Lower Kimmeridgian of Britain. (In this respect I cannot accept Arkell’s report of 
Lithacoceras from the Aulacostephanus zones (1947 : 73); or that of Ziegler of Sub- 
planites rueppellianus from the same beds (1962 : 13)). All reported instances of 
these genera must, in the absence of any figured evidence to the contrary, be inter- 
preted as occurrences of hitherto undescribed perisphinctids which in the author’s 
opinion do not belong either to Subplanites or Lithacoceras. 

The difference between Subplanites and Lithacoceras on the one hand, and Pectina- 
tites sensu lato on the other hand has not been recognized hitherto owing to the failure 
to take note of the different types of dimorphism in the two faunal provinces. As 
shown above, the microconchs of Pectinatites are horned, the macroconchs have a 
straight peristome and often a tendency towards virgatotome ribbing on the body- 
chamber. 

Subplanites and Lithacoceras both have lappeted microconchs, si) that microconchs 
with intact peristomes are easily distinguishable from microconchs of Pectinatites. 
However, several species of microconchs of Subplanites such as S. reist, S. schlossert, 
and S. moernsheimensis have polygyrate ribbing on their body-chamber, and are 
similar in adult size and rib-style to macroconchs of species of Pectinatites, but differ 
in that the former bear lappets whereas the latter do not. When material without 
intact peristomes is compared, therefore, the two forms are virtually indistinguish- 
able. Similarly Lithacoceras can be confused with Pectinatites when peristomes are 
not intact. Thus, previous comparisons of the British Kimmeridgian fauna to the 
Tithonian fauna have been comparisons between Kimmeridgian macroconchs and 
Tithonian microconchs. The similarity of the two faunas therefore must be regarded 
as an example of penecontemporaneous homeomorphy. 

However the similarity of the rib-style of the two faunas, in particular the presence 


24 UPPER KIMMERIDGE CLAY OF DORSET 


of polygyrate ribbing, strongly suggests that they were derived from the same stock. 
This presumably lay in some of the less specialized of the Lower Kimmeridgian 
ataxioceratids, or in such a genus as the Upper Oxfordian Discosphinctes which has 
some polygyrate ribs on the body-chamber. 

This being the case it would seem that Lithacoceras should be classified together 
with Subplanites and Pectinatites in the same sub-family. Arkell (1957) placed 
Lithacoceras in the sub-family Ataxioceratinae (Buckman 1921) whilst Subplanites 
and Pectinatites were assigned by him to the sub-family Virgatosphinctinae (Spath 
1923). Since these three genera are presumed to be derivatives of the ataxioceratid 
stock, and not themselves ataxioceratids, they perhaps should be all placed together 
in the sub-family Virgatosphinctinae. 


Subgenus ARKELLITES nov. 


Type SPECIES. Pectinatites (Arkellites) hudlestoni sp. nov. 


Diacnosis. Dimorphic. Microconchs fairly coarsely ribbed on inner whorls. 
Body-chamber generally more coarsely ribbed than inner whorls. Horn sometimes 
little more than an inflation of ventral part of peristome. Macroconchs with 
similarly ribbed inner whorls to those of microconchs. Outer whorl showing little 
or no variocostation, ribs little changed to the peristome. Some species showing 
strengthening of primary ribs with development of intercalatory secondary and 
unbranched primary ribs. Polygyrate ribs generally rare. Peristome simple. 
Constrictions if present shallow. Suture line unknown. 

Upper Kimmeridgian, Elegans to Hudlestoni Zones, ? Lower Pectinatus Zone. 


Pectinatites (Arkellites) primitivus sp. nov. 
(PIs nes: i. 25k 3) 

DiaGnosis. Macroconchs 125-150 mm. in diameter, with following rib densities: 
ates mith) 3032 tbs; ait 20) 32-345 025, 33=3590S0, 33-30 7=301 3enS 7 AO mae Sen 
45, 37-38; 50, 39; 55, 40; 60, 41; 65, 43. Ribs rectiradiate to prorsiradiate with 
wide angle of furcation. Outer whorl variable but typically with frequent un- 
branched primary ribs. Microconchs 80-105 mm. in diameter, with following rib 
densities: at 15 mm. 32 ribs; at 20, 32-36; 25, 33-37; 30, 34-38; 35, 35-38; 40, 36-40. 
Ribs rectiradiate or slightly prorsiradiate. Outer whorl variable with bifurcate ribs 
predominating, sometimes with polygyrate and simple ribs, and intercalatory 
secondaries. Peristome slightly inflated ventrally. 

HoLotyPe. Macroconch C.73392. 

PARATYPE. Macroconch C.73393. 

PARATYPES (ALLOTYPES). Microconchs C.73394, C.73395. 

MATERIAL. Nine specimens (four macroconchs, five microconchs). 


Horizon. Holotype, paratype and allotype C.73394, from 25 ft. below the Yellow 
Ledge Stone Band. Allotype C.73395 from 55 ft. below this band. 


NUMBER OF RIBS 


UPPER KIMMERIDGE CLAY OF DORSET 25 
; Se S 


40 


30 
45 


40 


\\ 

| 
LEN 

‘\ 

: 


tC 


30 
45 


40 
ieee 
Zz 
S 


30 eee 


WS} 25 35 45 55 65 


DIAMETER (MM.) 


Fic. 3. Rib density of species of the subgenus Arkellites. Upper case letters: macro- 
conchs ; lower case letters: microconchs. H, h: P. (A.) hudlestoni; D,d: P. (A.) 
damont; C,c: P. (A.) cuddlensis; P, p: P. (A.) primitivus. 


26 UPPER KIMMERIDGE CLAY OF DORSET 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Elegans Zone, between 12 
and 55 ft. below the Yellow Ledge Stone Band (see below). 


DESCRIPTION. Macroconch. Evolute shell with a diameter of 125-150 mm. 
Diameter of umbilicus 49-65 mm. The last whorl of the holotype has 54 primary and 
76 secondary ribs, while the last whorl of the paratype has approximately 48 primary 
and go secondary ribs. At 20 mm. diameter there are 34 ribs; at 25, 35; 30, 36; 
35, 36; 40, 37; 45, 37-38; 50, 39; 55, 40; 60, 41; 65, 43. The paratype has a 
similar rib-density. 

The ribs on the inner whorls are rectiradiate at the umbilical shoulder, then sweep 
forward to become prorsiradiate. (The few apparently rursiradial ribs on the 
holotype have been distorted by crushing.) The point of bifurcation of the ribs is 
high on the whorl side. The umbilical seam gradually uncoils over the last half- 
whorl. The ribs on the outer whorl are either bifurcate or simple. The angle of 
bifurcation is larger than in most of the species of this subgenus. The holotype 
shows no fewer than 19 simple ribs on its outer whorl. The paratype has fewer 
simple ribs (approximately 9) and at least one trifurcate rib. 

Microconch. Evolute shell with a diameter of between 80 and 105 mm. Diameter 
of umbilicus 32-40 mm. The last whorl of paratype C.73395 has approximately 
45 primary and 103 secondary ribs. At 15 mm. diameter there are 32 ribs, at 20, 
S235 25), SS=Sy/s Sh SHE9 Bop Sesids ZO), =A: 

The ribs on the inner whorl are rectiradiate at the umbilical shoulder but curve 
forwards and become straight and slightly prorsiradiate for the rest of their length. 
The point of bifurcation of the ribs is high on the whorl side. The umbilical seam 
uncoils over the last half whorl. The ribs on the outer whorl gradually become 
straight and rectiradiate. There are three simple ribs on the last whorl of paratype 
C.73394, otherwise the ribs are bifurcate. The other paratype shows several poly- 
gyrate ribs on the last whorl. The peristome is slightly inflated ventrally. 


Remarks. The macroconch of this species shows features which are interpreted 
as being primitive characters of the genus. These include the wide angle of furcation 
of the ribs, the abundant unbranched primary ribs, and the relative absence of 
trifurcate (polygyrate) ribs. The microconchs exhibit only a feeble ventral inflation 
of the peristome. The outer whorl of allotype C.73395 shows resemblance in its 
rib-style to microconchs of species of the sub-genus Virgatosphinctoides, but the 
coarser ribbing of the inner whorls of the former provides easy distinction. It is 
possible, however, that the subgenus Virgatosphinctotdes was derived from this species. 

Incomplete and poorly preserved ammonites from the lowest Hen Cliff Shales, 
and their basal cementstone, may belong to this species. This would extend the 
range of the species down to 70 feet below the Yellow Ledge Stone Band. 


Pectinatites (Arkellites) cuddlensis sp. nov. 
(Bie Piss etiget) 


Dracnosis. Large stoutly-ribbed Arkellites. Macroconchs 160-210 mm. in 
diameter, with following rib densities: at 30 mm., 34—40 ribs; at 35, 37-40; 40, 38-41; 


UPPER KIMMERIDGE CLAY OF DORSET 27 


45, 39-41; 50, 40-42; 55, 40-42; 60, 41-43; 65, 42-43. Ribs rectiradiate to slightly 
prorsiradiate. Outer whorl with mainly bifurcate ribs, but some unbranched primary 
and occasional polygyrate ribs, and intercalatory secondary ribs. Microconchs 
110-128 mm. in diameter, with following rib densities: at 15 mm., 33-34 ribs; at 20, 
34-36; 25, 35-37; 30, 35-38; 35, 36-39; 40, 36-41; 45, 37. Ribs of inner whorls 
similar in style to macroconch. Peristome with ventral horn 6—21 mm. long. 

HototyPeE. Macroconch C.733096. 

PARATYPE (ALLOTYPE). Microconch C.73397. 

MATERIAL. Nine specimens (five macroconchs, four microconchs). 


Horizon. Holotype from 18 ft. and paratype from 25 ft. above the Yellow Ledge 
Stone Band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, topmost Elegans to lower 
Scitulus Zones, 12 ft. below to 27 ft. above the Yellow Ledge Stone Band. 


DescripTIon. Macroconch. Evolute shell with a diameter of 160-210 mm. The 
holotype has a diameter of 206 mm., and an umbilical diameter of 94 mm. There are 
49 primary and 107 secondary ribs on the outer whorl of the holotype. At 30 mm. 
diameter the holotype has 34 ribs; at 35, 36; 40, 38; 45, 39; 50,40; 55,40; 60, 41; 
65, 42; 70, 43; 75,44; 80, 46; 85,47; 90, 48. The variation in rib density within 
the species is shown in Text-fig. 3. 

The ribs on the inner whorls are rursiradiate at the umbilical shoulder; they then 
swing forwards and become rectiradiate or slightly prorsiradiate and fairly straight. 
Some of the ribs on the inner whorls of the holotype are partially distorted by the 
crushing. The point of bifurcation of the ribs is high on the whorl-side. There is a 
slight uncoiling of the umbilical seam over the last half whorl. 

The ribs on the outer whorl become stronger and their furcation somewhat irregular, 
with the development of intercalatory secondary ribs, unbranched primary ribs, 
occasional trifurcate ribs, and occasional furcation low in the whorl-side. 

There do not appear to be any constrictions on the last whorl, although the rib 
style at one point (a trifurcate rib followed very closely by a simple rib) is very 
similar to that which obtains when a constriction is present. 

The peristome is simple. 

Microconch. Evolute shell with a diameter of 110-128 mm. Diameter of um- 
bilicus 42-47 mm. The last whorl of the paratype has 43 primary and 89 secondary 
ribs. At 15 mm. diameter the paratype has 33 ribs; at 30, 34; 25, 36; 30, 38; 
35, 39; 40, 41. The other microconchs of this species are similar to the paratype in 
rib density. (Text-fig. 3). 

The ribs on the inner whorls are similar in style to those of the macroconch. The 
umbilical seam uncoils over the last half whorl, which appears to correspond to the 
length of the body-chamber. The ribs on the outer whorl coarsen slightly and are 
more or less straight and rectiradiate. There are occasional simple and trifurcate 
ribs on the last whorl. 

The aperture bears a horn which is 21 mm. long on the paratype; the other complete 
microconchs have shorter horns, 


28 UPPER KIMMERIDGE CLAY OF DORSET 


REMARKS. This species has a similar, though not identical, density of ribbing 
on the inner whorls to that of P. (A.) primitivus, described above (p. 24). It differs, 
however, in adult size of both macroconch and microconch, and the density and 
style of ribbing of the outer whorl. It is probably, nevertheless, a derivative of this 
former species. 


Pectinatites (Arkellites) damoni sp. nov. 


(BES iss. 2, oe P16) 

Dracnosis. Macroconchs 136-160 mm. in diameter with following rib densities: 
at 25mm. 39 ribs; at 30, 40; 35, 40-41; 40, 41-42; 45, 41-42; 50, 42-43; 55, 43-45. 
Ribs rectiradiate to slightly prorsiradiate. Outer whorl with irregular ribs with 
fairly wide angle of furcation, occasional unbranched primary ribs. No trifurcate 
ribs. Microconchs 70-90 mm. in diameter with following rib densities: at 15 mm. 
34-35 ribs; at 20, 35-37; 25, 30-37; 30, 36-37; 35, 37-38. Ribs generally pror- 
siradiate. Outer whorl with occasional unbranched primary and polygyrate ribs. 
Peristome with ventral ribbed horn 3-15 mm. long. 


HototypPe. Macroconch C.73308. 

PARATYPE. Macroconch C.73399. 

PARATYPES (ALLOTYPES). Microconchs C.73400, C.73401. 

MATERIAL. Sixteen specimens (four macroconchs, twelve microconchs). 


Horizon. Holotype and allotypes from 25 ft., paratype from 27 ft. above the 
Yellow Ledge Stone Band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, lower Scitulus Zone, ranging 
between 15 and 32 ft. above the Yellow Ledge Stone Band. 


DEscRIPTION. Macroconch. Moderately evolute shell with a diameter of 130-160 
mm. Diameter of umbilicus 54-60 mm. The holotype has approximately 41 
primary ribs on the last whorl. No macroconch of this species with a complete last 
whorl has been found. At 25 mm. diameter the holotype has 39 ribs; at 30, 40; 
35, 40; 40, 41; 45, 41; 50, 42; 55, 43; 60, 43. The variation in rib density within 
the species is shown in Text-fig. 3. 

On the inner whorls the ribs are rursiradiate at the umbilical shoulder, they then 
swing forwards to become rectiradiate or slightly prorsiradiate and more or less 
straight. The point of bifurcation of the ribs is high on the whorl-side, and is not 
always visible on the innermost whorls. There is a slight uncoiling of the umbilical 
seam over the last half to three-quarters of a whorl. 

The ribs on the outer whorl are rather “ untidy” in appearance. They become 
coarser and have quite a wide angle of furcation. Occasional simple ribs are 
developed, but there is an absence of trifurcate ribs. No constrictions are visible. 

Although no specimen has its peristome preserved intact, it is presumably simple. 

Microconch. Evolute shell having a diameter of 702-90 mm. Diameter of um- 
bilicus 25-35 mm. The last whorl of paratype C.73400 has 42 primary and 86 
secondary ribs. The density of the ribs on the inner whorls can only be approxi- 


UPPER KIMMERIDGE CLAY OF DORSET 29 


mately determined on this specimen. Paratype C.73401 has 35 ribs at both 25 and 
30 mm. diameter. Other microconchs of the species show similar rib densities 
(Text-fig. 3). 

The ribs of the inner whorls are similar in style to those of the macroconch, but 
tend to be more prorsiradiate. On the outer whorl the forward inclination is not so 
pronounced, and the ribs approach the rectiradiate condition. The point of bifurca- 
tion of the ribs is quite high on the whorl-side, and is not always visible on the inner 
whorls. The umbilical seam uncoils gradually over the last half whorl. The length 
of the body-chamber (estimated by differences in the degree of crushing) is usually 
half a whorl long, but in some specimens it appears to be only about three-eighths of 
a whorl in length. 

The ribs on the outer whorl are slightly coarser than those of the inner whorls. 
There may be several simple and occasional trifurcate ribs on the last whorl. The 
ventral part of the peristome bears a horn which varies in length from 3-15 mm. and 
is always quite strongly ribbed. 


REMARKS. The macroconch of this species shows some similarity with that of 
P. (A.) primitivus, described above (p. 24). It differs in the density of ribbing of the 
inner whorls. The respective microconchs are not likely to be confused on account of 
size, rib style and density, and horn development. This species may, however, be 
derived from P. (A.) primitivus. Adult size of both macroconch and microconch, 
and the very irregular ribbing of the outer whorl distinguished P. (A.) damoni from 
P. (A.) cuddlensis. 


Pectinatites (Arkellites) hudlestoni sp. nov. 
(BZ tie a bh 7 Piss fie. 2) 

Diacnosis. Large Arkellites with stout blunt ribs. Macroconchs 170-196 mm. 
in diameter with following rib densities: at 15 mm. there are 29-31 ribs; at 20, 
4525313234; 302 32-35, 35, 34-375 40, 36-39; 45, 36-40; 50, 38-43; 55, 
40-44; 60, 42-45. Ribs rectiradiate to slightly rursiradiate. Ribs on outer whorl 
becoming blunt and massive, with abundant intercalatory secondary ribs and 
occasional unbranched primary ribs. Microconchs 72-112 mm. in diameter, with 
following rib densities: at 15 mm., 29-32 ribs; at 20, 30-34; 25, 31-36; 30, 31-39; 
35, 33-42; 40, 35-44; 45, 38-46. Ribs approximately rectiradiate, branching 
fairly low on whorl-side. Ribs coarser on outer whorl with occasional simple and 
rare polygyrate ribs. Peristome with well-developed ventral horn 4-21 mm. long. 
Horn ornamented only by growth lines. 


HototyrPe. Macroconch C.73403. 

PARATYPE (ALLOTYPE). Microconch C.73404. 

MATERIAL. Twenty-four specimens, including eleven plaster casts. Five macro- 
conchs, nineteen microconchs. 

Horizon. Holotype and paratype from shales 13 ft. above the Rope Lake Head 
Stone Band. 


30 UPPER KIMMERIDGE CLAY OF DORSET 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Hudlestoni Zone, from 12 ft. 
above the Rope Lake Head Stone Band to g ft. below the White Stone Band. 


Description. Macroconch. The dimensions given below are from the holotype 
which is the only reasonably complete macroconch which is well-preserved. 

Stoutly ribbed evolute shell with a diameter of 196 mm. Diameter of the umbilicus 
93mm. There are 42 primary and 96 secondary ribs on the last whorl. At 15 mm. 
diameter there are 31 ribs; at 20, 32: 25, 32; 30, 333-35, 34; 40, 36; 45,36; 50; 
38; 55, 40; 60, 42; 65, 42; 70, 43; 75, 44; 80, 45; 85, 46; 90, 46. The variation 
in rib density is shown in Text-fig. 3. 

The ribs on the inner whorls have a slight rursiradial curve at the umbilical 
shoulder; for the rest of their length they are straight and rectiradiate, or slightly 
rursiradiate. The point of bifurcation is high on the whorl-side apart from occasional 
ribs which branch near the umbilical shoulder. The umbilical seam uncoils over the 
last five-eighths of a whorl. 

On the outer whorl the ribs gradually become blunt and massive. The primary 
ribs branch to give only two secondary ribs; no trifurcate ribs are developed. There 
are, however, abundant intercalatory secondary ribs, and one or two simple ribs. 

The peristome is not preserved completely, but in the absence of any contrary 
evidence, is assumed to be simple. 

Miucroconch. Evolute shell with a diameter of 72-112 mm. Diameter of the 
umbilicus 26-45 mm. The paratype has a diameter of 98 mm. and an umbilical 
diameter of 44 mm. It has 55 primary and r1o secondary ribs on its outer whorl. 
At 15 mm. diameter the paratype has 31 ribs, at 20, 33; 25, 35; 30, 36; 35, 39; 
40, 40; 45,42. The variation in rib density is shown in Text-fig. 3. 

The ribs on the inner whorls are of similar style to those of the macroconch, but 
the point of bifurcation is somewhat lower on the whorl-side. The umbilical seam 
uncoils over the last half whorl. 

The ribs on the last whorl gradually become coarser; occasional simple ribs are 
developed, and very rarely a trifurcate rib. 

The peristome is straight and has a well developed ventral horn. On the paratype 
the horn projects 20 mm. from the venter, but it may be asshortas4mm. The horn 
itself is ornamented only by growth lines, the ribs on the whorl-side fading as they 
approach the venter in the vicinity of the horn. 

REMARKS. This species is younger in age than other species of this subgenus 
recorded hitherto. It is distinguished by its rib-style, particularly the tendency for 
the ribs of the macroconch to be slightly rursiradiate. The microconch horn also 
tends to be free of ornamentation. On some specimens (e.g. C.73402 figured in 
Pl. 2, fig. 3) the venter bears scars, suggesting that earlier formed horns may have 
been shed. 


Subgenus VIRGATOSPHINCTOIDES Neaverson 1925 : II 


1925 Allovirgatites Neaverson : 29. 


TYPE SPECIES. Vuirgatosphinctoides wheatleyensis Neaverson 1925. 


URPBRER IGCIMMERTEDGE CMAY OF DORSET 31 


Diacnosis. Dimorphic. Macroconchs generally finely ribbed on inner whorls. 
Outer whorl very variable; primary ribs strong and typically with frequent poly- 
gyrate furcation, and often a tendency to become fasciculate or virgatotome; second- 
ary ribs obsolescent in some large species. Variocostation slight to pronounced. 
Peristome simple. Microconchs similarly ribbed on inner whorls to macroconchs. 
Body-chamber usually more coarsely ribbed than inner whorls. Peristome typically 
with well-developed ventral horn, more rarely only with ventrally inflated peristome. 
Constrictions commonly present, particularly in macroconchs. 

Upper Kimmeridgian, Elegans to Hudlestoni Zones. 


Pectinatites (Virgatosphinctoides) elegans sp. nov. 


(RISS hiesera 10. Pi) 

Diacnosis. Macroconchs 154—184 mm. in diameter with following rib densities: 
at 15 mm. diameter there are approximately 37 ribs; at 20, 38; 25, 39; 30, 39-42; 
35, 40-43; 40, 41-45; 45, 42-46; 50, 43-47; 55, 44-48; 60, 45-49; 65, 46-50. 
Ribs slightly prorsiradiate, fairly straight. Outer whorl developing strengthened 
primary ribs, mainly bifurcate, but with occasional simple and polygyrate ribs and 
intercalatory secondaries. Microconchs 100-112 mm. in diameter with following 
rib densities: at 20 mm. diameter there are 39-44 ribs; at 25, 40-45; 30, 41-45; 35, 
42-46; 40, 44-47. Ribs of inner whorls similar to macroconch, outer whorl slightly 
more strongly ribbed with occasional simple and polygyrate ribs. Peristome with 
ventral inflation projecting 4-8 mm. 


Hototyrr. Macroconch C.73405. 
PARATYPE (ALLOTYPE). Microconch C.73406. 
MATERIAL. Fifteen specimens (six macroconchs, nine microconchs). 


Horizon. Holotype from 18 ft. and paratype from 20 ft. below the Yellow 
Ledge Stone Band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Elegans Zone, between 50 and 
16 ft. below the Yellow Ledge Stone Band. 


DESCRIPTION. Macroconch. Evolute shell with a diameter of 154-184 mm. 
Diameter of the umbilicus 65-76 mm. There are 61 primary and 137 secondary 
ribs on the last whorl of the holotype. At 40 mm. diameter the holotype has 45 ribs, 
at 45, 66; 50, 47; 55, 48; 60, 48; 65, 49; 70,50. The variation in rib density is 
shown in Text-fig. 4. 

The sharp dense ribs on the inner whorls are slightly prorsiradiate and straight 
for most of their length, but at the umbilical shoulder are rectiradiate or rursiradiate 
as with other species of this subgenus. The point of bifurcation of the ribs is very 
high on the whorl side. The umbilical seam uncoils over the last half-whorl. 

The ribs on the outer whorl are similar in style to those of the inner whorls but 
gradually become more blunt and more widely spaced. Occasional simple and 
polygyrate ribs are developed on the outer whorl, but bifurcate ribs predominate. 

The peristome is simple. 


32 UPPER KIMMERIDGE CLAY OF DORSET 


| 
ay 


60 


\ 


LTR 


[ 


\\ 
‘OS ae 


NUMBER OF RIBS 


ta TAN 


Be Pe 
ae 


40 


Wh | TY 
WWE 
Aes |) 


a 
i Era 


35 


iS 25 35 45 58) 65 


DIAMETER (MM.) 


Fic. 4. Rib density of species of the subgenus Virgatosphinctoides. Upper case letters : 
macroconchs ; lower case letters: microconchs. W,w: P. (V.) woodwardi; D,d: P. 
(V.) decorosus; S,s: P. (V.) scitulus; E, e: P. (V.) elegans. 


UPPER SIMMER EDGE ICLAY OF DORSET 33 


Microconch. Evolute shell with a diameter of 100-112 mm. Diameter of the 
umbilicus (paratype) 40 mm. The paratype has 66 primary and approximately 
130 secondary ribs on the last whorl. At 15 mm. diameter the paratype has approxi- 
mately 42 ribs; at 20, 44; 25, 45; 30,45; 35,46; 40,47. The variation in rib density 
is shown in Text-fig. 4. 

The rib style of the inner whorls is very similar to that of the macroconch. The 
umbilical seam uncoils over the last half whorl. No suture is visible, but differences 
in the degree of crushing suggest that the body-chamber is half a whorl in length. 
The ribs on the last half whorl become slightly coarser, and occasional simple and 
trifurcate ribs are developed. The peristome curves forward ventrally and is 
inflated on the ventral margin which projects 8 mm. on the paratype. The ribs 
pass uninterrupted over the projection. 


REMARKS. This is the earliest known species of the subgenus Virgatosphinctordes. 
The origin of the subgenus may have been from P. (Arkellites) primitivus described 
above (p. 24), the microconch of which shows a broadly similar rib style to this species, 
It is readily distinguished, however, by the much more finely ribbed inner whorls 
and the pronounced peristomal inflation. P.(V.) elegans is distinguished from later 
species of the subgenus by its rib-density, the peristomal development of the micro- 
conch and the body-chamber ornament of the macroconch. 


Pectinatites (Virgatosphinctoides) elegans corniger subsp. nov. 


(Pro) 


DiaGnosis. Macroconch approximately 125 mm. in diameter with following 
approximate rib densities: at 30 mm. 48 ribs; at 35, 49; 40, 50; 45, 5I; 50, 52. 
Ribs prorsiradiate, fairly straight. Outer whorl developing strengthened primary 
ribs with fairly frequent polygyrate ribs. Microconch 82-85 mm. in diameter with 
following rib densities: at 20 mm. diameter approximately 43 ribs; at 25, 45; 30, 46. 
Inner whorls similarly ribbed to macroconch, outer whorl slightly more coarsely 
ribbed with occasional simple and polygyrate ribs. Peristome with ventral horn 
up to 7 mm. long. 

HoLotypPe. Macroconch, C.73407. 

PARATYPES (ALLOTYPES). Microconchs. C.73408, C.73409. 

MaTERIAL. The holotype and two paratypes. 


Horizon. Holotype and paratype C.73408 from 5 ft., and paratype C.73409 
from 8 ft. below the Yellow Ledge Stone Band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, topmost Elegans Zone, between 
5 and 8 ft. below the Yellow Ledge Stone Band (see below). 


DescripTion. Macroconch. Evolute shell with an estimated diameter of 123 mm. 
Diameter of the umbilicus 50 mm. The last whorl has approximately 53 primary 
ribs. The number of secondary ribs cannot be determined since a part of the outer 
whorl has been broken away. At 39 mm. diameter there are 48 ribs; at 35, 49; 
40, 50; 45, 51; 50, 52. 


GEOL, 15, I. 3 


34 UPPER KIMMERIDGE CLAY OF DORSET 


The ribs on the inner whorls are of a similar style to those of P. (A.) elegans 
described above but tend to be a little more prorsiradiate. The point of bifurcation 
of the ribs is high on the whorl side. The umbilical seam uncoils over the last half 
whorl. The last umbilical whorl shows the development of occasional trifurcate and 
simple ribs; these become more numerous on the outer whork, where there is some 
degree of variocostation. Over the last half whorl the primary ribs become more 
widely spaced and more pronounced, and there are frequent polygyrate ribs. 

The peristome is not completely preserved, but is presumably simple. 

Microconch. Evolute shell with a diameter of 82-85 mm. Diameter of the 
umbilicus 28-32 mm. There are 55-63 primary and 122~130 secondary ribs on the 
last whorl. At 20 mm. diameter there are 43 ribs; at 25, 45; 30, 46. 

The rib style of the inner whorls is similar to that of the macroconch. The umbili- 
cal seam uncoils over the last half whorl, which appears to correspond to the length 
of the body-chamber, to judge by differences in the degree of crushing. 

The ribs on the outer whorl are of similar style to those of the inner whorls, but 
become slightly coarser with the tendency to develop occasional polygyrate and 
simple ribs. The peristome is curved forwards dorsally, and ventrally has a horn 
which is 7 mm. long on paratype C.73408. The secondary ribs pass uninterrupted 
over the horn. 


REMARKS. One fragment of an ammonite possibly belong to this subspecies was 
collected from the Yellow Ledge Stone Band, thus the stratigraphical range of the 
subspecies may extend upwards to the top of the Elegans Zone. 

The subspecies is intermediate in many respects between P. (V.) elegans (p. 31) and 
P. (V.) scitulus (p. 34). It is intermediate in age between the two, and shows charac- 
ters of both species. It is distinguished from the former species by the smaller adult 
size of both its macroconch and microconch, the peristomal development of the 
microconch, and the more strongly ribbed body chamber of the macroconch. Dis- 
tinction from the latter species is based on the adult size of the macroconch and 
microconch, the perstomal development of the microconch, and the ribbing on the 
body-chamber of the macroconch which is not so markedly variocostate as in P. (V.) 
scitulus. The rib-density of the subspecies shows a closer relationship to P. (V.) 
scitulus than to P. (V.) elegans; however, the subspecies is assigned to the latter 
species because the ornament of the body-chamber of the macroconch, and the ribbed 
horn of the microconch show more affinity to the developments of these characters in 
P.(V.) elegans. This subspecies appears to form a direct phylogenetic link between 
P. (V.) elegans and P. (V.) scitulus. 


Pectinatites (Virgatosphinctoides) scitulus sp. nov. 


(2iers) 


Dracnosis. Macroconchs 130-162 mm. in diameter with following rib densities: 
at 30 mm. diameter approximately 48 ribs; at 35, 46-49; 40, 46-49; 45, 47-49; 50, 
48-49; 55, 49-50; 60, 49-50; 65, 49-51. Ribs rectiradiate to slightly prorsiradiate, 
straight. Outer whorl with strengthened primary ribs and variable number of 


UPPER KIMMERIDGE CLAY OF DORSET 35 


simple and polygyrate ribs with occasional intercalatory secondary ribs. Micro- 
conchs 67-82 mm. in diameter with following rib densities: at 20 mm. diameter 
42-44 ribs; at 25, 44-46; 30, 45-47; 35, 48. Inner whorls similar to macroconch. 
Outer whorl with slightly stronger ribs with tendency to be flexuous, and with 
occasional simple and polygyrate ribs. Peristome with feebly-ribbed ventral horn 
7-16 mm. long. 


HototypPE. Macroconch C.7341I. 
PARATYPE (ALLOTYPES). Microconchs C.73412, C.73413. 
MATERIAL. Twenty-two specimens (ten macroconchs, twelve microconchs). 


Horizon. Holotype from 24 ft. above the Yellow Ledge Stone Band. Paratypes 
from 25 and 15 ft. respectively above this band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, lower half of Scitulus Zone, 
occurring in the Yellow Ledge Stone Band and up to 44 ft. above this horizon. 


DEscrIPTION. Macroconch. Evolute shell with a diameter of 130-162 mm. The 
holotype is 162 mm. diameter. Diameter of the umbilicus 50~78 mm. There are 
47 primary and 99 secondary ribs on the last whorl of the holotype, other specimens 
have similar rib density on the last whorl. At 30 mm. diameter the holotype has 
48 ribs; at 35, 49; 40, 49; 45, 49; 50, 49; 55,50; 60, 50; 65, 51; 70, 52; 75, 52. 
The variation in the rib density is shown in Text-fig. 4. 

The ribs on the inner whorls are dense and sharp. At the umbilical shoulder there 
is a slight rursiradial curve; the ribs then swing forwards and become straight and 
rectiradiate or slightly prorsiradiate. The point of bifurcation of the ribs is high on 
the whorl-side. The umbilical seam uncoils over the last half whorl. 

The outer whorl develops coarser ribs; the primary ribs become more widely 
spaced, and there is the development of simple and polygyrate ribs, and intercalatory 
secondary ribs. There appear to be several constrictions of the shell over the last 
whorl, but the crushing does not allow this to be definitely ascertained. There is 
considerable variability in the sculpture of the outer whorl, some specimens having 
very frequent polygyrate ribs. The peristome is simple. The length of the body- 
chamber is unknown. 

Microconch. Evolute shell with a diameter of 67-82 mm. Diameter of the 
umbilicus 25-32 mm. Paratype C.73413 has 45 primary and g2 secondary ribs on 
the last whorl; other specimens have similar rib density on the last whorl. At 
20 mm. diameter there are 42 ribs; at 25, 44; 30,45. Variation in rib density ofthe 
inner whorls is shown in Text-fig. 4. 

The ribs on the inner whorls are identical in style to those of the macroconch. The 
umbilical seam uncoils over the last half whorl. Differential crushing suggest 
that the body-chamber varies in length from half to five-eighths of a whorl. 

The outer whorl has somewhat coarser ribs which tend to be a little flexuous. At 
the umbilical shoulder they are rursiradiate, then swing forwards to become slightly 
prorsiradiate, rectiradiate, or slightly rursiradiate. There are occasional simple and 
polygyrate ribs on the last whorl, which may have a few constrictions. 


30 UPPER KIMMERIDGE CLAY OF DORSET 


The peristome has a ventral horn which varies in length from 7 to 16 mm. The 
horn is only feebly ribbed. 


REMARKS. ‘The points of distinction between this species and P. (V.) elegans and 
P. (V.) elegans corniger have been discussed above (p. 34). It is readily distinguished 
from P. (V.) decorosus described below (p. 36) by the rib density of the inner whorls. 


Pectinatites (Virgatosphinctoides) decorosus sp. nov. 


(Pi 2) 


Diacnosis. Macroconchs 120-140 mm. in diameter with following rib densities: 
at 30 mm. diameter there are 41 ribs; at 35, 41; 40, 41-42; 45, 41-42; 50, 41-42. 
Ribs of inner whorls fairly straight and prorsiradiate; outer whorl developing coarser 
more widely spaced rectiradiate ribs, with occasional constrictions followed by 
simple unbranched primary rib. Microconchs approximately 85 mm. in diameter 
with following approximate rib densities: at 25 mm. diameter there are 38 ribs; 
at 30, 39; 35, 42. Inner whorls ribbed similarly to macroconch, outer whorl with 
stronger rectiradiate ribs, occasionally simple or polygyrate. Peristome with ventral 
horn up to 9 mm. long. 


Hototyre. Macroconch C.73414. 

PARATYPE (ALLOTYPE). C.73415. 

MATERIAL. Eight specimens (four macroconchs, four microconchs). 

Horizon. Holotype and paratype from 15 ft. above the Yellow Ledge Stone Band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Scitulus Zone, 15 to 30 ft. above 
the Yellow Ledge Stone Band. 


DescripTION. Macroconch. Evolute shell with a diameter of 120-140 mm. 
Diameter of the umbilicus 54-66 mm. The last whorl of the holotype has 43 primary 
and approximately 96 secondary ribs. At 30 mm. diameter there are 41 ribs; at 
35, 41; 40, 41-42; 45, 41-42; 50, 41-42. 

The ribs on the innermost whorls are very slender and delicate; they are fairly 
straight and slightly prorsiradiate. An initial rursiradial curve then develops at 
the umbilical shoulder; the ribs then swing forwards to become prorsiradiate. The 
point of bifurcation of the ribs is quite high on the whorl side. The umbilical seam 
uncoils over the last half whorl. 

The ribs on the outer whorl gradually become coarser and more widely spaced, 
and lose most of their initial rursiradial curve to become fairly straight throughout 
their length. They are mainly rectiradiate, but vary from slightly rursiradiate to 
slightly prorsiradiate. There appear to be four or five constrictions on the outer 
whorl of the holotype. These are usually preceded by a polyploke rib, formed by 
the fusion close to the umbilical shoulder of two bifurcate ribs, and are always followed 
by a simple rib. Apart from these modifications, and the occasional intercalatory 
rib, all the ribs are bifurcate. 

The peristome is simple. 


UPPER KIMMERIDGE CLAY OF DORSET 37 


Microconch. Evolute shell with a diameter of approximately 85 mm. All the 
measurements given are from the paratype which is the only well-preserved micro- 
conch. Diameter of the umbilicus 35 mm. The last whorl has 46 primary and 
approximately 90 secondary ribs. At 25 mm. diameter there are 38 ribs; at 30, 39; 
35, 42. 

The rib style on the inner whorls is similar to that of the macroconch. The um- 
bilical seam uncoils over the last half whorl (which is estimated to be the length of 
the body-chamber). The ribs on the outer whorl are strong and rectiradiate; they 
are mainly bifurcate, but there are occasional simple and polygyrate ribs. 

The peristome has a ventral horn of moderate length (9 mm. on the paratype) 
and which is ribbed. It arises gradually as an extension of the venter, and does not 
project very sharply as is the case in several other species of the genus. 


REMARKS. The density and style of ribbing of this species render it readily 
distinguishable from allied species such as P. (V.) scitulus described above (p. 34). 
The rib density of the inner whorls shows some similarity to that of P. (A.) cuddlensis 
described above (p. 26), but adult size, rib style, and rib density of the outer whorl 
differ markedly in the two forms. 


Pectinatites (Virgatosphinctoides) major sp. nov. 


(Pin) 

Dracnosis. Very large Virgatosphinctoides with little varicocostation. Diameter 
approximately 240-320 mm., with following rib densities: at 50 mm. diameter there 
are 42-47 ribs; at 60, 44-48; 70, 46-50; 80, 48-51; 90, 49-53; I00, 50-55; ITO, 
51-55; 120, 52-56; 130, 54-56; 140, 57. Ribs of inner whorls slender, rectiradiate 
to prorsiradiate; outer whorl with stronger rectiradiate ribs, with some simple and 
polygyrate ribs. 

HototyrPe. Macroconch C.73410. 

MATERIAL. Ten specimens (all macroconchs). 

Horizon. Holotype from 6 ft. below the Yellow Ledge Stone Band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Upper part of Elegans Zone 
and Scitulus Zone, 20 ft. below the Yellow Ledge Stone Band up to the Cattle Ledge 
Stone Band. 


DEscriPTION. Macroconch. Evolute shell with a diameter of 240-320 mm. 
The diameter of the umbilicus varies from 130-150 mm. The holotype is 318 mm. 
in diameter, has an umbilical diameter of 140 mm., and 59 primary and 124 secondary 
ribs on the last whorl. At 5o mm. diameter it has 46 ribs; at 55,47; 60, 48; 65, 49; 
mOn5O 775,50; 80,515785, 52; 90; 53; 95, 54; 100, 55; 105,55; 110,55; 115, 55; 
120, 56; 125, 65; 130, 56; 135, 57; 140, 57: 

The ribs on the inner whorls are slightly rursiradiate at the umbilical shoulder, 
and then bend forwards and become either rectiradiate or slightly prorsiradiate. 
The point of bifurcation of the ribs occurs fairly high on the whorl-side. The um- 
bilical seam uncoils over the last half whorl, The length of the body-chamber is 


NUMBER OF RIBS 


38 


UPPER KIMMERIDGE CLAY OF DORSET 


O 


DIAMETER (MM) 


Fic. 5. Rib density of species of the subgenus Vivgatosphinctoides. G: P. (V.) grandis ; 


P: P. (V.) pseudoscruposus; M: P. (V.) major; L: P. (V.) laticostatus. 


UPPER KIMMERIDGE CLAY OF DORSET 39 


unknown, but would appear to be greater than two-thirds of a whorl, if the differential 
crushing is a reliable guide. The ribs on the outer whorl gradually lose their initial 
rursiradial curve, and become rectiradiate throughout. There is little variocostation 
in this species, and the ribs of the outer whorl remain predominantly bifurcate. 
There are, however, occasional simple and more rarely polygyrate ribs. The holo- 
type shows, in addition, one rib near the smooth peristome margin, which bifurcates 
very low on the whorl-side and again higher on the whorl, producing a total of four 
secondary ribs. This type of furcation (polyploke) is not seen on any other specimen 
of the species, otherwise the other specimens show little variation from the holotype, 
except that some of the specimens from higher horizons tend to develop a slightly 
lower point of furcation of the ribs on the body-chamber. 

The microconch of this species is unknown. 

REMARKS. The very large size of this species renders it readily distinguishable 
from other species of Pectinatites of the same age. It may be distinguished from 
other large species of the genus (all of which, described hitherto, are of younger age) 
by the very small degree of variocostation. 


Pectinatites (Virgatosphinctoides) clavelli sp. nov. 


(Pl. 14) 


Diacnosis. Macroconchs 2ro—260 mm. in diameter with following approximate 
rib densities: at 40 mm. diameter there are 46 ribs; at 50, 49; 60, 54-57; 70, 55-61; 
80, 56-66. Ribs of inner whorls slender and rectiradiate. Outer whorl developing 
widely-spaced massive blunt primary ribs with frequent polygyrate furcation, and 
intercalatory secondary ribs. Microconchs 67-87 mm. diameter with following 
rib densities: at 25 mm. diameter there are 42 ribs; at 30, 43-44; 35, 44. Inner 
whorls similarly ribbed to macroconch. Outer whorls somewhat more coarsely- 
ribbed with occasional polygyrate and simple ribs. Peristome projecting ventrally 
by up to 5 mm. 

HototyrPe. Macroconch C.73432. 

PARATYPES (ALLOTYPES). Two microconchs, C.73433, C.73434. 


MATERIAL. Eleven specimens, all plaster casts (five macroconchs, six micro- 
conchs). 


Horizon. Holotype from 8 ft., and paratypes from 3 ft. above the Grey Ledge 
Stone Band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, lower Wheatleyensis Zone, 
between 3 and 28 ft. above the Grey Ledge Stone Band. 


Description. Macroconch. Large evolute shell with a diameter of approximately 
210-260 mm. The diameter of the umbilicus varies from 104 to 130 mm. 

The last whorl of the holotype which is 212 mm. in diameter has 51 primary and 
an estimated 122 secondary ribs. The innermost whorls are not completely preserved 
inany onespecimen. At 60mm. diameter the holotype has 57 ribs, at 70, 62; 80, 66; 
90, 69; 100, 71. The variation in rib density is shown in Text-fig. 6. 


NUMBER OF RIBS 


Ge 
' 
: 


40 


UPPER KIMMERIDGE CLAY OF DORSET 
Tae i, ae 
60 
1 oe 
Eo | a et 
nade ee 


: 
K 
A 


50 


: 
nae 
Hise e 
pe 


Pile 
RIES 
AN 
ite 


a) 


15 25 35 45 SS) 65 


DIAMETER (MM) 


Fic. 6. Rib density of species of the subgenus Virgatosphinctoides. Upper case letters : 
macroconchs ; lower case letters: microconchs. W, w: P. (V.) wheatleyensis; C, c: 
P. (V.) clavelt; S,s: P. (V.) smedmorensis; m: P. (V.) magnimasculus ; E,e: P. (V.) 
encombensis ; A; P. (V.) abbreviatus, 


UPPER KIMMERIDGE CLAY OF DORSET 41 


The ribs on the inner whorl are rursiradiate at the umbilical shoulder; they then 
swing forwards and become straight and more or less rectiradiate. The point of 
bifurcation of the ribs is high on the whorl-side. There is a marked uncoiling of 
the umbilical seam over the last half whorl. 

The ribs on the outer whorl become coarser, and the primary ribs become more 
widely spaced and irregular in their style and furcation. Some are rursiradiate, 
others rectiradiate or prorsiradiate. Several of the primary ribs show polygyrate 
furcation, and there is also a profusion of simple and intercalatory ribs on the last 
whorl. 

The peristome is simple. 

Microconch. Evolute shell considerably smaller than the macroconch, having a 
diameter of only 68-87 mm. The diameter of the umbilicus is 30-37 mm. There 
are 46 primary and 94 secondary ribs on the last whorl of paratype C .73434. The 
rib style of the inner whorls is similar to that of the macroconch. At 25 mm. diameter 
there are 42 ribs; at 30, 43-44; at 35,44. (Text-fig. 6). 

The point of bifurcation of the ribs is high on the whorl-side. The umbilical seam 
uncoils noticeably over the last half whorl. 

The outer whorls of both specimens are rather distorted by the crushing so that 
it is not easy to deterine the original rib direction. It would appear, however, to 
be rursiradiate at the umbilical shoulder, then becoming straight and rectiradiate. 
There are occasional simple ribs on the last whorl and a few primary ribs with three, 
or in one case, four secondary ribs. 

The ventral part of the perstome bears a short ribbed horn 4-5 mm. in length. 
It arises gradually from the venter and is not well preserved on either paratype. 


RemArRKS. The adult diameter of the macroconch and microconch, their rib 
density, and the development of the microconch horn, serve to distinguish this 
species from others. P. (V.) smedmorensis described below is considerably more 
coarsely ribbed than this species. As the highest beds of the underlying Scitulus 
Zone have hitherto yielded no ammonites, it is not possible to determine the origin 
of this species. The degree of variocostation of the macroconch is more pronounced 
than that of P. (V.) scztulus, but the general rib style of the two species shows some 
similarities. The very irregular costation of the body-chamber of the macroconch 
is a feature characteristic of many of the younger species of the subgenus Vzrgato- 
sphinctoides. The development of the microconch horn in this species is not, however, 
very typical. 


Pectinatites (Virgatosphinctoides) smedmorensis sp. nov. 


(Pl. 15, figs. 1, 2) 

Diacnosis. Macroconchs approximately 150 mm. in diameter with following 
approximate rib densities: at 60 mm. diameter there are 39-41 ribs; at 65, 39-41; 
70, 40-42; 75, 41-43; 80, 42. Ribs on inner whorls slender and prorsiradiate 
becoming rursiradiate with strengthening of primary ribs on body-chamber. Poly- 
gyrate, simple and intercalatory secondary ribs occur occasionally. Constrictions 
developed over last two whorls. Microconchs 86-107 mm, in diameter with following 


42 UPPER KIMMERIDGE CLAY OF DORSET 


approximate rib-densities: at 20 mm. diameter there are 34 ribs; at 25, 25; 30, 27; 
35, 38. Ribs of inner whorls similar in style to macroconch, becoming a little coarser 
on outer whorl. Peristome bearing ventral horn up to 8 mm. long. 


HoLotyre. Macroconch, plaster cast C-73430. 
PARATYPE (ALLOTYPE). Microconch, plaster case C -73431. 


MATERIAL. Five specimens, including three macroconchs (two of which are 
plaster casts, and two microconchs (both plaster casts)). 


Horizon. Both type specimens are from 22 ft. below the Blackstone. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, lower Wheatleyensis Zone, 
from 8 ft. above the Grey Ledge Stone Band, to 22 ft. below the Blackstone (A 
vertical range of 41 ft.). 


Description. Macroconch. FEvolute shell with a diameter of approximately 
150 mm. Diameter of the umbilicus approximately 85 mm. At 60 mm. diameter 
the holotype has 39 ribs; at 65, 39; 70, 40; 75, 41; 80, 42. (Text-fig. 6). 

The ribs on the inner whorls are rectiradiate at the umbilical shoulder, then swing 
forwards to become fairly straight and prorsiradiate. The point of bifurcation of 
the ribs is fairly high on the whorl-side. The umbilical seam uncoils over the last 
half to three-quarters of a whorl. 

The ribs on the outer whorl gradually lose their prorsiradiate tendency and become 
straight and slightly rursiradiate throughout their length. The primary ribs become 
more widely spaced and very sharp, and the development of the secondary ribs 
becomes irregular. There are occasional polygyrate, simple and intercalatory ribs. 

There are several constrictions present. On the last half-whorl these are straight 
and are followed by a simple rib. The constrictions developed earlier are quite 
pronouncedly prorsiradiate, however. These oblique constrictions are preceded by 
a trifurcate rib which branches low on the whorl-side, and are followed by a simple 
rib. 

A part of the suture line is present on one specimen; it is not well-preserved, 
however, but does show stout saddles and lobes. Both lateral lobes appear to be 
trifid. 

The peristome is not completely preserved on any specimen but is presumably 
simple. 

Mucroconch. Neither microconch is particularly well or completely preserved. 
Both specimens are plaster casts. The paratype is quite evolute and has a diameter 
of 86 mm. The diameter of the umbilicus is 36 mm. There are an estimated 46 
primary ribs on the last whorl. 

The ribs of the inner whorls are similar in style to those of the macroconch. At 
20 mm. diameter there are 34 ribs; at 25, 35; 30, 37; 35, 38. (Text-fig. 6). 

The outer whorl has ribs of similar style, but they become a little coarser. There 
is one possible constriction present at the aperture. 

The ventral part of the peristome is damaged, but there is visible the basal 3 mm. 
of a horn, the original length of which may have been 7-8 mm. 


REMARKS. Most characters of this species are sufficiently distinctive to separate 


UPPER KIMMERIDGE CLAY OF DORSET 43 


it from other species. It is distinguished from P. (V.) clavelli described above (p. 39) 
by the smaller adult size of the macroconch and the more coarsely-ribbed inner 
whorls. The microconch has a similar rib-density on its inner whorls to that of 
P. (V.) woodwardi (p. 45), but may be distinguished by the rib-style of both inner 
and outer whorls. 


Pectinatites (Virgatosphinctoides) laticostatus sp. nov. 


(Pl. x6) 


Diacnosis. Large Virgatosphinctoides developing massive widely-spaced primary 
ribs over last two whorls. Diameter 230-320 mm., with following approximate 
rib densities: at 20 mm. diameter there are 38 ribs; at 30, 42; 40, 45; 50, 47; 60, 
e270; 49-55, 80; 49-55; 90; 47-50; 100; 45-53; 110, 43-51; 120, 40-49 
130, 38-45. Ribs of inner whorls rectiradiate to prorsiradiate becoming more widely 
spaced from ante-penultimate whorl onwards. Outer whorl extremely coarsely 
ribbed with abundant intercalatory secondary ribs. Microconch unknown. 


Hototyre. Plaster cast C.73416. 
MATERIAL. Six specimens, including two plaster casts (all macroconchs). 
Horizon. Holotype from “ dicey ” shales 19 ft. below the Blackstone. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, lower Wheatleyensis Zone 
ranging from 3 ft. above the Grey Ledge Stone Band to 13 ft. 6 in. below the Black- 
stone (a vertical range of 47 ft.). 


DEscriIpTIon. Large evolute shell with a diameter of 232-320 mm. Diameter of 
umbilicus 130-180 mm. The holotype has 27 primary and approximately 68 
secondary ribs on the last whorl. At 20 mm. diameter holotype has approximately 
38 ribs; at 30, 42; 40,45; 50, 47; 60, 48; 70, 49; 80, 49; 90, 47; 100, 45; ITO, 43; 
120, 40; 130, 38. The variation in rib density is shown in Text-fig. 5. 

The ribs on the innermost whorls are rursiradiate at the umbilical shoulder then 
swing forwards to become rectiradiate or slightly prorsiradiate. A coarsening of 
the ribs develops very early, and the last three whorls become progressively more 
coarsely ribbed. There is a gradual loss of the initial rursiradial curve of the ribs 
and they become straight throughout their length. The point of bifurcation of the 
ribs is high on the whorl-side, and the angle of furcation is somewhat larger (at least 
on the outer whorls), than is usual in this subgenus. The umbilical seam uncoils 
over the last half whorl. 

The outer whorl becomes extremely coarsely ribbed and abundant intercalatory 
secondary ribs are developed. 

At least two constrictions are present on the holotype, one on the penultimate and 
one on the antepenultimate whorl; they are both strongly oblique. In each case 
the constriction is preceded by a biplicate rib, which branches very close to the 
umbilical shoulder. A simple rib follows the constriction. 

The peristome is not preserved intact on the holotype, but is presumed to be simple. 

The microconch of this species has not been found hitherto. 


44 UPPER KIMMERIDGE CLAY OF DORSET 


REMARKS. The very early development of widely-spaced ribs in this species is an 
uncommon character in this subgenus, and is therefore a very useful character for 
identification of this species. The problematical Virgatosphinctoides nodiferus 
Neaverson (1925 : 14, pl. 4, fig. 1) has a similar style of nbbing on its outer whorl, 
but its rib-development is not known in any detail. It is apparently geologically 
younger than P. (V.) laticostatus. 


Pectinatites (Virgatosphinctoides) grandis (Neaverson) 
(Pi a5 ities 35 Pie 18) 
1925 Virgatosphinctoides grandis Neaverson : 13, pl. 4, fig. 2. 
MATERIAL. Eight specimens; seven macroconchs, one possible microconch. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, upper part of Wheatleyensis 
Zone, between 3 and 17 ft. below the Blackstone. 


DeEscrIPTION. Macroconch. There is good agreement between one of the speci- 
mens here figured (Pl. 18) and the holotype, which came from Corton, Dorset. The 
former has a diameter of 365mm. The umbilicus has a diameter of 168mm. There 
are 24 primary and approximately 82 secondary ribs on the last whorl. At 80 mm. 
diameter there are 86 ribs, at go, 87; 100, 85; 110, 85; 120, 79; 130, 77; 140, 71; 
150, 68; 160, 64. The variation in rib-density of the Kimmeridge forms is shown 
in Text-fig. 5. 

The ribs on the inner whorls are rursiradiate at the umbilical shoulder and gradually 
swing forwards, so that less than half way up the whorl-side they become prorsi- 
radiate. On the last umbilical whorl the ribs become more widely spaced, until on 
the outer whorl the primary ribs are very strong and distant from one another. 

There are often large numbers of secondary ribs to each primary rib. On some 
specimens there are regularly as many as five secondary ribs to each primary rib. 
The ribs become straighter on the last part of the body-chamber and slightly prorsi- 
radiate throughout their length. The secondary ribs tend to become less prominent 
and several primary ribs may be unbranched. Some intercalatory secondary ribs 
are usually present on the last whorl. There are several constrictions present. 
They are preceded by a compound rib, and followed by a simple rib. 

The peristome is presumably simple. 

Microconch. The figured microconch comes from the same horizon (17 ft. below 
the Blackstone) as the earliest recorded macroconch of this species. 

It is 112 mm. in diameter. The diameter of the umbilicus is 45 mm. There are 
approximately 70 primary ribs on the last whorl. At 40 mm. diameter there are 
approximately 68 ribs. The ribs of the inner whorl are similar in style to those of 
macroconch. The outer whorl is similarly ribbed, but has occasional simple and 
polygyrate ribs and at least one constriction. The aperture bears a horn which 
projects from the venter by about 7 mm. 

RemMArKS. There is a great disparity in size between the microconch (112 mm. 
diameter) and the associated macroconch (approximately 280 mm. diameter). 
However, it has been found that as a general rule the microconch is usually slightly 


UPPER KIMMERIDGE CLAY OF DORSET 45 


coarser-ribbed than its macroconch at the same diameter. In this case the micro- 
conch has 68 ribs at 45 mm. diameter while the macroconch has approximately 70 at 
this diameter. No other fine-ribbed macroconchs occur at this horizon, so that there 
can be little doubt that this specimen is the microconch of P. (V.) grandis. 

The size of this species, coupled together with rib-style and density distinguish it 


from other species of the genus. 


Pectinatites (Virgatosphinctoides) grandis acceleratus subsp. nov. 


(Pl. 19) 


Diacnosis. Very large Virgatosphinctoides. General characters similar to P. 
(V.) grandis (Neaverson) but development of modified ornament occurring earlier. 
Ribs of outer whorl blunt and massive with few secondaries. Some intercalatory 
secondary ribs. 


HorotyPe. Macroconch C.73422, the only specimen. 


Horizon. 13 ft. above the Rope Lake Head Stone Band. (Upper Kimmeridgian, 
basal part of Hudlestoni Zone). 


DESCRIPTION. Large evolute shell with a diameter of approximately 375 mm. 
Diameter of the umbilicus 175 mm. There are 23 primary and approximately 60 
secondary ribs on the last whorl. 

This subspecies is similar in most respects to P. (V.) grandis described above. It 
differs in that it becomes coarser-ribbed earlier in development, but the different 
types of sculpture present in P. (V.) grandis are repeated in the same order, but at 
smaller diameters. 

The peristome is simple. 


REMARKS. This subspecies is closely related to P. (V.) grandis and must be 
interpreted as a direct derivative of it. There is, however, a thickness of approxi- 
mately 35 ft. of rock between the highest recorded occurrence of P. (V.) grandis 
and the horizon from which this subspecies came. Most of the intervening rocks, 
however, are extremely poorly fossiliferous, so that collection failure is most probably 
responsible for the “ break ”’. 

No microconch of this subspecies has been found hitherto. 


Pectinatites (Virgatosphinctoides) woodwardi (Neaverson) 


(Pl. 20) 


1925 Allovirgatites woodwardi Neaverson : 31, pl. 3, fig. 1. 
1925 Allovirgatites robustus Neaverson : 32, pl. 3, fig. 3. 

1925 Allovirgatites versicostatus Neaverson : 32, pl. 3, fig. 4. 
1926 Allovirgatites woodwardi Neaverson ; Buckman, pl. 637. 


MATERIAL. Eleven specimens (five macroconchs, six microconchs). 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Wheatleyensis Zone (just above 
the middle), ranging between 15 and g ft. below the Blackstone. 


40 UPPER KIMMERIDGE CLAY OF DORSET 


DerscripTION. Macroconch. Fairly evolute shell with a diameter of 150-185 mm. 
Diameter of umbilicus 74-88 mm. The last whorl of the specimen here figured 
which is approximately 155 mm. diameter has an estimated 46 primary and 111 
secondary ribs. The innermost whorls are not completely preserved in any specimen. 
At 50 mm. diameter there are 49 ribs, at 55,52; 60,54; 65,55; 70,56. (Text-fig. 4). 

The ribs on the inner whorls are rursiradiate at the umbilical shoulder, then swing 
forwards to become rectiradiate or slightly prorsiradiate and more or less straight. 
The point of bifurcation of the ribs is high on the whorl-side. 

The umbilical seam uncoils over the last half-whorl. (This uncoiling is not notice- 
able in the plate reproduced herein, owing to the crushing of the last umbilical whorl 
which gives an incorrect impression of the amount of this whorl exposed.) 

The ribs on the outer whorl become more widely spaced and stouter. The point 
of furcation is sometimes lower on the whorl-side. The number of secondary ribs 
per primary is variable, with as many as four secondary ribs to each primary rib. 
There are at least two possible constrictions on the outer whorl. The peristome is 
not preserved intact on any specimens, but is presumably simple. 

Microconch. Fairly evolute shell with a diameter of approximately 68-77 mm. 
The diameter of the umbilicus is 25~30 mm. The figured specimen has 49 primary 
and an estimated 92 secondary ribs on its last whorl. At 20 mm. diameter there are 
approximately 34 ribs; at 25, 35; 30, 36. The variation in rib density is shown in 
Text-fig. 4. 

The inner whorls are similar in rib style to those of the macroconch. The umbilical 
seam uncoils over the last half whorl (not well-shown on the figured microconch). 

The ribs of the outer whorl lose most of their initial rursiradial curve and are almost 
straight and rectiradiate. There is some slight variability in the rib direction, 
however, from slightly rursiradiate to slightly prorsiradiate. There are occasional 
simple and trifurcate ribs on the last whorl. 

The peristome is not preserved intact on any one specimen. The figured specimen 
shows it to be more or less straight, however. The ventral part of the peristome on 
this specimen projects about 2 mm. and is then broken, so that it is safe to conclude 
that a horn was originally present. 


REMARKS. The Dorset specimens agree closely with Neaverson’s figure of Allo- 
virgatites woodward. A. robustus Neaverson is merely an incomplete specimen of the 
same species, apparently a little thicker-whorled, but still very close to the former 
species. A. versicostatus Neaverson is also very close to this species and may possibly 
be the microconch. The differences do not appear to be sufficient to warrant specific 
distinction. The association of P. (V.) woodward: with P. (V.) wheatleyensis (Neaver- 
son) is also indicative of the similarity of the Dorset to the Oxford material. 


Pectinatites (Virgatosphinctoides) wheatleyensis Neaverson 


(2d Airc) 


1925 Vuivgatosphinctoides wheatleyensis Neaverson : 12, pl. 1, fig. 1. 
19560 Subplanites (Virgatosphinctoides) wheatleyensis (Neaverson) Arkell: 779, pl. 40, fig. 1. 


MATERIAL. Eleven specimens (five macroconchs, six microconchs). 


WWZNE NTIS TCIM LID RAID (End) (CLA 6 (Oy IDO Sl Bh 47 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Wheatleyensis Zone (just above 
the middle), ranging from 15 to g ft. below the Blackstone. 


DESCRIPTION. Macroconch. One specimen from Kimmeridge here figured, 
(Pl. 21, fig. 1) agrees extremely closely with the holotype figured by Neaverson. It 
has a diameter of 132 mm. The diameter of the umbilicus is 57 mm. There are 
approximately 64 primary and 156 secondary ribs on the last whorl. Another speci- 
men, which has well preserved inner whorls, has rib density as follows: at 25 mm. 
diameter there are 54 ribs, 30, 54; 35, 553 40, 57; 45, 58; 50, 58; 55, 60. The 
variation in rib density of the Kimmeridge specimens is shown in Text-fig. 6. 

The ribs on the inner whorls are rursiradiate at the umbilical shoulder, then swing 
forwards to become rectiradiate or slightly prorsiradiate. The point of bifurcation of 
the ribs is high on the whorl-side. The umbilical seam uncoils on the last half whorl. 

The outer whorl is very variable. The primary ribs become more widely spaced 
and are mostly polygyrate in some specimens. Others show the persistence of a 
more conservative type of ribbing, with more bifurcate than polygyrate ribs. 

One specimen shows the last few approximated suture lines, but as these are 
extremely poorly preserved, comparison with the suture line figured by Neaverson 
(1925, text-fig. B, 5) is not possible. However, it can be seen from these suture lines 
that the body-chamber is half a whorl in length. 

The peristome is simple and straight. 

Microconch. One specimen figured herein (C. 73426) has a diameter of 91 mm. The 
diameter of the umbilicus (which is somewhat elongated by crushing) is 36 mm. 
There are 56 primary and 122 secondary ribs on the last whorl. The inner whorls 
are badly preserved, so that it is not possible to determine the rib density accurately. 
There are, however, approximately 50 ribs at 35mm. diameter. The other figured 
specimen (C. 73427) has at 15 mm. diameter 47 ribs, at 20, 47; 25, 48; 30, 49. 
(Text-fig. 6). 

The ribs on the inner whorls are of a similar style to the macroconch. The umbili- 
cal seam uncoils over the last half whorl (which appears to correspond to the length 
of the body-chamber). 

The ribs on the outer whorl become slightly coarser, and there is the development 
of occasional polygyrate and simple ribs. 

The peristome bears a horn when completely preserved, and this is 17 mm. long 
on specimen C. 73426. It is quite strongly ribbed. 

ReMARKS. The horizon at which this species occurs in Dorset is much lower 
than that quoted by Arkell (1947 : 71). Although the ammonites from just below 
the Basalt Stone Band are undoubtedly somewhat similar in appearance to this 
species, the outer whorls are not the same. The associated fauna also confirms the 
identity of this species. Neaverson placed his Wheatleyensis Zone immediately 
above the Gvavesia Zones, which is too low in the succession. 


Pectinatites (Virgatosphinctoides) wheatleyensis minor subsp. nov. 
(Pli24 tie? 2) 
Dracnosis. Macroconchs small (103-108 mm. diameter) with following approxi- 


48 UPPER KIMMERIDGE CLAY OF DORSET 


mate rib densities: at 25 mm. diameter there are 44 ribs; at 30, 48; 35, 46; 40, 48; 
45, 49. Ribs of inner whorls slender and approximately rectiradiate. Outer whorl 
developing strengthened primary ribs, remaining approximated, with polygyrate 
furcation predominant. 2 
HoLtotyre. Macroconch C.73429. 
MATERIAL. Two specimens (both macroconchs). 


Horizon. Both specimens from 17 ft. below the Blackstone (Upper 
Kimmeridgian, middle Wheatleyensis Zone). 


DESCRIPTION. Evolute shell with a diameter of 103-108 mm. (small for a macro- 
conch). Diameter of umbilicus 43-45mm. There are approximately 53 primary and 
144 secondary ribs on the last whorl. In rib style this subspecies is very similar to 
P. (V.) wheatleyensis, but is somewhat more coarsely ribbed. At 20 mm. diameter 
there are approximately 44 ribs, at 30, 45; 35, 46; 40, 48; 45, 49. The point of 
bifurcation of the ribs is high on the whorl-side. The umbilical seam uncoils over 
the last half-whorl. The ribs on the outer whorl are identical in style with those of 
the holotype of P. (V.) wheatleyensis, being mostly polygyrate. 

The peristome is simple. 


REMARKS. The microconch of this subspecies is not known. Apart from the 
somewhat more coarsely ribbed inner whorls, and smaller adult size, this subspecies 
is similar to P. (V.) wheatleyensis. Its lower stratigraphical horizon suggests that 
it is a possible ancestor of this species. 


Pectinatites (Virgatosphinctoides) wheatleyensis delicatulus (Neaverson) 


(Piz7, tie. 2) 


1925 Vuirgatosphinctoides delicatulus Neaverson : 15, pl. 1, figs. 2 and ?3. 
1925 Allovirgatites tutcheri Neaverson : 30, pl. 3, fig. 2. 
1926 Allovirgatites tutcheyi Neaverson ; Buckman, pl. 692. 


MATERIAL. Five specimens (four macroconchs, one possible microconch). 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Wheatleyensis Zone (upper part) 
between 7 and 4 ft. below the Blackstone (see below). 


DescripTIon. Macroconch. The Dorset specimens agree closely with Neaver- 
son’s figure of the holotype, but are complete individuals. One specimen with a 
diameter of approximately 130 mm. and an umbilical diameter of 53 mm. has about 
78 primary and 151 secondary ribs on the last whorl. The ribs on the inner whorl 
are a little finer and more dense than those of P. (V.) wheatleyensis. Some specimens 
have several constrictions of the last umbilical and the outer whorl. 

The main point of difference between this subspecies and P. (V.) wheatleyensis 
lies in the more finely ribbed outer whorl, and the constrictions which are usually 
present. The constrictions are preceded by a polygyrate or polyploke rib and are 
followed by a simple rib. In some cases this rib is prominent like the flare of Lyto- 
ceras. (As is the case with Neaverson’s examples). 

The peristome is simple. The body-chamber is a half whorl in length. 


UPPER KIMMERIDGE CLAY OF DORSET 49 


Microconch. <A single poorly preserved specimen from 5 ft. below the Blackstone 
is possibly the microconch of this subspecies. It is gt mm. in diameter, has an 
umbilical diameter of 35 mm. and has approximately 56 primary and 112 secondary 
ribs on the last whorl. The inner whorls are so hidden by pyrite aggregates, however, 
that it cannot be with certainty referred to this subspecies. 

The umbilical seam uncoils over the last half whorl. The peristome is missing, 
but was presumably originally horned. 


RemARKS. Allovirgatites tutcheri Neaverson differs from Virgatosphinctoides 
delicatulus Neaverson by no more than the difference between two individuals of the 
same species. The general similarity to P. (V.) wheatleyensts justifies separation only 
at subspecific level. 

This subspecies, which is stratigraphically a little younger than P. (V.) wheat- 
leyensis, is certainly a derivative of it. One specimen which I refer to P. (V.) 
wheatleyensis 1s similarly ribbed to this subspecies on the inner whorls, but is inter- 
mediate between the two forms in the ribbing of its outer whorl. 

Several very poorly preserved ammonites from the shales 4-10 ft. above the 
Blackstone are provisionally included in this subspecies. 


Pectinatites (Virgatosphinctoides) pseudoscruposus (Spath) 


(Bik 7) 
1936 Subplanites pseudoscruposus Spath : 173, fig. 2. 
1947 Subplanites pseudoscruposus Spath; Arkell: 77, fig. 17, I. 

EMENDED DIAGNOsIS. Diameter of shell 220-230 mm. with following rib densities: 
at 40 mm. diameter there are approximately 51 ribs; at 50, 53-57; 60, 55-01; 70, 
60-66; 80, 66-71; 90, 70-76; 100, 75-78. Ribs on inner whorls slender and 
prorsiradiate. Outer whorl developing massive blunt primary ribs typically with 
virgatotome furcation, with up to six secondary ribs to each primary. 


MATERIAL. Six specimens (all macroconchs). 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Wheatleyensis Zone (upper 
part), between 9 and 3 ft. below the Blackstone. 


DESCRIPTION. Large evolute shell with a diameter of 220 to approximately 230 
mm. Diameter of umbilicus 110+115 mm. The specimen figured herein (C.73418) 
has 36 primary and approximately 104 secondary ribs on the last whorl (about one- 
eighth of a whorl is missing). 

At 50 mm. diameter this specimen has 57 ribs, at 60, 59; 70, 66; 80, 72; 90, 76; 
100, 77; 110, 78. The variation in rib density is shown in Text-fig. 5. 

The ribs on the inner whorls are fine and slender. They are curved rursiradially 
at the umbilical shoulder, but swing forwards rapidly to become prorsiradiate and 
almost straight. The point of bifurcation of the ribs is high on the whorl-side. The 
umbilical seam uncoils over the last half to three-quarters of a whorl. 

The sculpture of the outer whorl is extremely variable, no two specimens being 
alike in this respect. Typically there are developed very prominent blunt primary 


GEOL, I5, I. 4 


50 UPPER KIMMERIDGE CLAY OF DORSET 


ribs which tend to become virgatotome, with up to six secondary ribs. There are 
occasional simple and intercalatory secondary ribs. 

Constrictions are also present on the last whorl of some specimens of this species. 
These are preceded by a virgatotome rib with four or five secondary ribs, and are 
followed by a simple rib. 

The microconch of this species is unknown. 


REMARKS. The validity of this species may be questioned, as it does not entirely 
fulfil the requirements of Article 13 of the International Code of Zoological Nomen- 
clature. However, the outer whorl fragment upon which Spath based this species is 
absolutely characteristic and there can be no doubt of its interpretation. Spath’s 
figure is misleading in that the inner whorls he associated with the outer whorl 
fragment almost certainly belong to a different species. The name of this species is 
well-known to those familiar with British Kimmeridgian ammonites, and there would 
seem to be little to be gained by rejecting a name because its original description was 
legally defective. The intention here has been to give a more satisfactory definition 
of the species by figuring a more complete specimen and giving a comprehensive 
description. 


Pectinatites (Virgatosphinctoides) reisiformis sp. nov. 


(Ply 225 See 2eticas) 

Dracnosis. Macroconchs 155-255 mm. in diameter with following rib densities: 
at 20 mm. diameter there are 48-52 ribs, at 25, 49-54; 30, 52-560; 35, 54-58; 40 
55-58; 45, 50-59; 50, 57-01; 55, 58-63; 60, 59-64; 65, 60-65; 70, 61-66. Ribs 
of inner whorls slender and prorsiradiate. Outer whorl becoming suddenly more 
coarsely-ribbed with polygyrate then virgatotome ribs, with abundant simple and 
intercalatory secondary ribs. Microconchs 78-110 mm. in diameter with following 
rib densities: at 20 mm. diameter there are approximately 42 ribs; at 25, 42-44; 
30, 43-40; 35, 44-47; 40, 46-49; 45, 48-52. Ribs of inner whorls similar to 
macroconch. Outer whorl more coarsely ribbed with occasional simple and poly- 
gyrate ribs and intercalatory secondaries. Peristome with ventral horn 10-20 mm 
long. 

HorotyrPe. Macroconch C.73435. 

PARATYPE (ALLOTYPE). Microconch C.73436. 

MATERIAL. Twenty-five specimens (seventeen macroconchs, eight microconchs). 


Horizon. Both holotype and paratype are from shales 13 ft. above the Rope Lake 
Head Stone Band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, uppermost Wheatleyensis and 
basal Hudlestoni Zones, from 6 ft. above the Blackstone to 16 ft. above the Rope 
Lake Head Stone Band. 


DESCRIPTION. Macroconch. Evolute shell with a diameter of 155-255 mm. 
Diameter of umbilicus 65-118 mm. The holotype has a diameter of 174 mm., and 
an umbilical diameter of 76 mm. There are 51 primary and 118 secondary ribs on 


NUMBER OF RIBS 


UPPER KIMMERIDGE CLAY OF DORSET 51 


80 


intersex 


pe it ee 


EP 


heal 2 PS 


Hehaiain tis 


repel ae 
Hicen 
ies 


Cass 


ate 
Nim 


Beet 
Beebe pe Pi) y\ 


= 
mil 


45 
15 25 35 45 33) 65 


DIAMETER (MM,) 
Fic. 7. Rib density of species of the subgenus Virgatosphinctoides. Upper case letters : 


macroconchs ; lower case letters: microconchs. RD, rd: P. (V.) veisiformis densi- 
costatus; R,r: P. (V.) reisiformis; D, d: BP. (V.) donovani. 


52 UPPER KIMMERIDGE CLAY OF DORSET 


the last whorl. The inner whorls are well preserved on the holotype. At 20 mm. 
diameter there are 48 ribs, at 25, 49; 30, 52: 35,54; 40,55; 45,56; 50,573 55, 58; 
60, 59; 65,60; 70, 61; 75,62. The variation in rib density is shown in Text-fig. 7. 

The ribs on the inner whorls are dense and slender. They are rursiradiate at the 
umbilical shoulder, then swing forwards to become prorsiradiate (pronouncedly so 
in some specimens). The point of bifurcation of the ribs is high on the whorl-side. 
The umbilical seam uncoils over the last half to three-quarters of a whorl. 

On the outer whorl the ribs become rather suddenly more widely spaced. At first, 
polygyrate ribs are developed; then as the primary ribs become stouter and blunter, 
the branching has a tendency towards the virgatotome condition, with up to four 
secondary ribs to each primary rib. There are abundant simple and intercalatory 
ribs on the last whorl. 

The ribbing of the outer whorl is extremely variable in this species. No two speci- 
mens are alike in this respect. Some of the larger specimens are obviously gerontic 
individuals, the last secreted half whorl or so of their shell being almost devoid of 
ornament. 

The peristome is not preserved on the holotype, but other specimens show it to be 
straight and simple. 

Microconch. Evolute shell with a diameter of 78-110 mm. The diameter of the 
umbilicus varies from 30-42 mm. The paratype is 110 mm. in diameter and has an 
umbilical diameter of 42 mm. There are 63 primary and 126 secondary ribs on the 
last whorl of the paratype. At 25 mm. diameter the paratype has 44 ribs, at 30, 45; 
35, 47; 40, 48. The variation in rib density is shown in Text-fig. 7. 

The ribs of the inner whorls are similar in style to those of the macroconch, but 
tend not to be so markedly prorsiradiate. The point of bifurcation of the ribs is a 
little lower on the whorlside than on the macroconchs. The umbilical seam uncoils 
over the last half whorl. 

The outer whorl becomes more coarsely ribbed, and there is a tendency for the ribs 
to become somewhat flexuous. At, or just below the point of furcation, the ribs 
bend back a little. This feature is well shown on the paratype. Almost all the ribs 
on the outer whorl are bifurcate, but there are very occasional simple, polygyrate, 
and intercalatory ribs. 

The peristome is somewhat sinuous, and laterally extends anteriorly a little. There 
is a well developed ventral horn, which is often feebly ribbed. On the paratype the 
horn projects from the venter by about 18 mm. In some specimens growth has 
proceeded a little beyond the horn; this anteriorly extended portion of the shell 
shows little or no ornamentation. 


RemARKS. The density of the ribbing on the inner whorls, and the sculpture of 
the outer whorl are distinctive features of this species. It may be derived from P. (V.) 
wheatleyensis but shows considerably more variocostation than this latter species. 
The diversity of the ornamentation of the body-chamber of the macroconchs con- 
trasts with the rib-density of the inner whorls which are remarkably similar in rib 
style and density. 


UPPER KIMMERIDGE CLAY OF DORSET 53 


Pectinatites (Virgatosphinctoides) reisiformis densicostatus subsp. nov. 
(Rikzs Migswt a2. sPia2y. fie. 2) 


Diacnosis. Macroconchs 150-195 mm. in diameter with following rib densities: 
at 20 mm. diameter there are 52-58 ribs; at 25, 55-60; 30, 56-63; 35, 60-65; 40, 
ea=07 45, 05-72, 50, 08-74; 55, 70-70; 60, 73-77; 65, 75-79. ‘Ribs of inner 
whorls slender and prorsiradiate. Outer whorl developing strengthened primary 
ribs, first with polygyrate and polyploke furcation, then with tendency to virgatotome 
furcation. Microconchs 77-110 mm. diameter with following rib densities: at 20 
mm. diameter there are 47—50 ribs; at 25, 48-52; 30, 50-54; 35, 51-55; 40, 51-50. 
Ribs of inner whorls slender and prorsiradiate, becoming somewhat coarser on outer 
whorl with occasional polygyrate and simple ribs. Peristome with ventral horn 
12-24 mm. long. 

Hototyre. Macroconch C.73437. 

PARATYPE. Microconch C.73438. 

MATERIAL. Twenty-eight specimens (fourteen macroconchs, thirteen micro- 
conchs, one intersex). 


Horizon. Both holotype and paratype from shales 13 ft. above the Rope Lake 
Head Stone Band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, lower part of Hudlestoni Zone, 
12-16 ft. above the Rope Lake Head Stone Band. 


DeEscripTIoNn. Macroconch. Evolute shell with a diameter of 150-195 mm. 
Diameter of the umbilicus 63-87 mm. The holotype is 157 mm. in diameter and 
has an umbilical diameter of 67 mm_ There are 64 primary and r4r secondary ribs 
on the last whorl. At 15 mm. diameter there are about 52 ribs; at 20, 58; 25, 60; 
30, 63; 35, 63; 40, 65; 45, 65; 50, 68; 55,70; 60,74; 65,75. The variation in 
rib density is shown in Text-fig. 7. 

In style of ribbing on both inner and outer whorls this subspecies agrees closely 
with the description of P. (V.) reisiformis given above (p. 50). It differs, however, 
in being far more densely ribbed throughout. The ribs themselves are also a little 
more slender. 

Microconch. Evolute shell with a diameter of 77-110 mm. Diameter of the 
umbilicus 27-42 mm. The paratype has a diameter of 83 mm. and an umbilical 
diameter of 30mm. There are 67 primary and 132 secondary ribs on the last whorl. 
At 15 mm. the paratype has an estimated 46 ribs, at 20, 50; 25, 50; 30,52. The 
variation is rib density is shown Text-fig. 7. 

The rib style on the inner whorls is similar to that of the microconch of P. (V.) 
veistformis, but the ribs are usually a little more prorsiradiate and are more slender. 

On the outer whorl the ribs become a little coarser, and occasional polygyrate and 
simple ribs are developed. 

The peristome margin may be straight or sinuous, a horn is developed ventrally, 
and on the paratype projects from the venter by 16 mm. In some cases growth has 
proceeded a little beyond the growth of the horn, and there is a fairly smooth zone 


54 UPPER KIMMERIDGE CLAY OF DORSET 


anterior to this. In other cases a further horn may be grown close to the first one. 

Intersex. This subspecies is particularly interesting because of a probable mutation 
which arose resulting in the development of inter-sexual individuals. One 
specimen (C.73439, Pl. 24, fig. 2) is intermediate in size between macroconch and 
microconch (117 mm. diameter) and has rib density of a typical microconch up to a 
diameter of 30 mm. (20, 47; 25, 49; 30, 52). Thereafter it becomes more finely 
ribbed (35, 56; 40, 58), and is intermediate between macroconch and microconch in 
rib density. (Text-fig. 7). 

At a diameter of 94 mm. a horn is developed, and beyond this there is about three- 
eighths of a whorl of coarsely ribbed shell with sculpture similar to the outer whorls 
of a macroconch, but bearing four further horns. The development in this subspecies 
of the macroconch outer whorl sculpture at such a small diameter is unique to this 
specimen. 

In addition to the above specimen which is absolutely intermediate in character 
between macroconch and microconch, three other specimens show a slight degree of 
intersexuality. These three specimens are apparently normal macroconchs to judge 
by their size, rib density and sculpture. They do, however, develop a type of horn 
in the later stages of development; this appears at a diameter of 140-150 mm. and 
is unlike the true microconch horn in that it is developed from a single rib, has 
negligible ventral projection but projects laterally some distance down the whorl 
side. In addition, the diameter at which these structures are developed is much 
greater than that at which the true horn of the microconch occurs. 

These three latter specimens possess some degree of microconch character. 

REMARKS. This subspecies shows a general similarity to P. (V.) vezsiformis 
described above. It may readily be distinguished, however, by the rib density of 
the inner whorls. Because of this likeness to P. (V.) vezsiformis, the similar horizon 
of the two forms (this subspecies is confined to the beds yielding the youngest speci- 
mens of P. (V.) veisiformis) tends to confirm the view that it should be considered a 
direct derivative of P. (V.) reisiformis. 


Pectinatites (Virgatosphinctoides) abbreviatus sp. nov. 


(BIN267 figs) 

Dracnosis. Macroconchs small (113-125 mm. in diameter) with following rib 
densities: at 20 mm. diameter there are 40-42 ribs; at 25, 41-43; 30, 42-44; 35, 
44-45; 40, 454-6; 45, 46. Ribs on inner whorls slender, rursiradiate to rectiradiate. 
Primary ribs becoming more widely spaced and stronger on outer whorl, with develop- 
ment of simple and polygyrate ribs. Microconchs unknown. 


HoLotyPe. Macroconch C.73440. 
MATERIAL. Three specimens (all macroconchs). 
Horizon. Holotype from shales 20 ft. above the Rope Lake Head Stone Band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Hudlestoni Zone (lower part), 
20-22 ft. above the Rope Lake Head Stone Band. 


UPPER KIMMERIDGE CLAY OF DORSET 55 


DeEscriIPTION. Macroconch. Evolute shell with a diameter of 113-125 mm. 
Diameter of umbilicus 45-59 mm. The holotype has a diameter of 113 mm. and 
an umbilical diameter of 45mm. There are 47 primary and 96 secondary ribs on the 
last whorl. At 15 mm. diameter the holotype has 39 ribs; at 20, 40; 25, 41; 30, 42; 
35, 44; 40, 45; 45, 46. The variation in rib density is shown in Text-fig. 6. 

The ribs on the inner whorls are rursiradiate at the umbilical shoulder, they then 
bend forwards to become rectiradiate. Some of the ribs are, however, rursiradiate 
throughout their length. The point of bifurcation is high on the whorl-side. The 
umbilical seam uncoils over the last half whorl. 

On the outer whorl, the ribs gradually become coarser, and on the last half whorl 
(which to judge by differences in the crushing corresponds to the length of the body- 
chamber) the primary ribs become widely spaced. Several simple, polygyrate and 
intercalatory ribs are developed. 

The peristome is damaged on all the specimens, but on the holotype it is partially 
preserved and appears to be straight and simple. 

The microconch of this species is unknown. 

REMARKS. This species is notable for the small size at which the macroconch 
becomes mature. For this reason it is unlikely to be confused with any other species 
of the genus. P. (V.) wheatleyensis minor is of similar size, but the outer whorl of 
this subspecies is ornamented by approximated mainly polygyrate ribs; this contrasts 
with the more widely spaced primary ribs of P. (V.) abbreviatus. 


Pectinatites (Virgatosphinctoides) donovani sp. nov. 


(Bi25, fess ke2) 

DiaGnosis. Macroconchs 132-155 mm. in diameter with following rib densities: 
at 30 mm. diameter there are approximately 51 ribs; at 35, 51; 40, 51-53; 45, 
51-54; 50, 52-55; 55, 53-55; 60, 55-50. Ribs on inner whorls slender and prorsi- 
radiate. Outer whorl with strong irregular primary ribs with frequent polygyrate 
furcation. Simple and intercalatory secondary ribs abundant. Ribs fading slightly 
over last quarter of whorl. Microconchs 99-106 mm. in diameter with following 
approximate rib densities: at 30 mm. diameter there are 46 ribs; at 35, 48; 40, 49; 
45, 50. Ribs of inner whorls similar to macroconch. Outer whorl developing 
somewhat strongcr ribs with occasional simple and intercalatory ribs and polygyrate 
furcation. 


HoLotyrPe. Macroconch C.73441. 

PARATYPE (ALLOTYPE). Microconch C.73442. 

MATERIAL. Ten specimens, all plaster casts, (six macroconchs, four micro- 
conchs). 

Horizon. Holotype from 30 ft. and paratype from 36 ft. below the Basalt Stone 
Band. 

STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Hudlestoni Zone (middle part), 
30-40 ft. below the Basalt Stone Band. 


56 UPPER KIMMERIDGE CLAY OF DORSET 


DESCRIPTION. Macroconch. Evolute shell with a diameter of 132-155 mm. 
The diameter of the umbilicus varies from 59-69 mm. The holotype has a diameter 
of 137 mm. and an umbilical diameter of 65 mm. The last whorl of the holotype has 
46 primary and ror secondary ribs. At 40 mm. diameter the holotype has 52 ribs, 
at 45, 53; 50,53; 55,54; 60,55; 65,56. The variation in rib density is shown in 
Text-fig. 7. 

The ribs on the inner whorl are rectiradiate at the umbilical shoulder, then curve 
forwards to become fairly straight and prorsiradiate. At the point of bifurcation, 
which is high on the whorl-side, the ribs curve back a little to the rectiradiate position. 
The umbilical seam uncoils over the last half to three-quarters of a whorl. 

On the outer whorl the ribs gradually lose their initial rursiradial curve. The 
primary ribs become very strong and irregular, and the point of furcation is lower on 
the whorl-side. There are abundant simple, polygyrate and intercalatory ribs on the 
last whorl. Over the last quarter of a whorl, the ribs tend to fade somewhat, and 
although easily distinguishable, are not so prominent. 

The peristome is somewhat sinuous and is simple. 

Microconch. Evolute shell with a diameter of gg-106 mm. Diameter of the 
umbilicus 42-47 mm. The paratype has a diameter of 105 mm. and an umbilical 
diameter of 45mm. The last whorl of the paratype has 49 primary and 96 secondary 
ribs. At 30 mm. diameter the paratype has 46 ribs, at 35, 48; 40, 49; 45,50. The 
variation in rib density is shown in Text-fig. 7. 

The ribs on the inner whorls are of similar style to those of the macroconch. The 
umbilical seam uncoils over the last half whorl (which appears to correspond to the 
length of the body-chamber, to judge by differences in the degree of crushing). 

On the outer whorl the ribs become rather suddenly more widely spaced half a 
whorl from the aperture. These coarser ribs are rather irregular in their furcation; 
most are bifurcate, but there are several simple, polygyrate and intercalatory ribs. 

The peristome is not completely preserved on any microconch of this species The 
dorsal part of it appears to be straight, but no specimen shows the whole of the 
ventral part which was presumably horned. The ventral part of the peristome of 
the paratype appears to project by some 5 mm., but is not well-preserved at this 
point. 

REMARKS. This species appears to be the one misidentified by Arkell as P. (V.) 
wheatleyensis (Arkell 1956 : 21). As I have shown earlier, however (p. 47), the 
true P. (V.) wheatleyensis occurs considerably lower in the succession, where it is 
associated with other species also characteristic of the Nodule Bed of Wheatley. 
The rib density and ornamentation of the body-chamber of P. (V.) donovani 
distinguish it from P. (V.) wheatleyensis. 


Pectinatites (Virgatosphinctoides) magnimasculus sp. nov. 


(Pl. 29) 
Dracnosis. Microconchs very large (175-185 mm. in diameter) with following 
approximate rib densities: at 25 mm. there are 54 ribs; at 30, 55; 35,57; 40, 57; 
45,59; 50,60; 55,62; 60,62. Ribs of inner whorls slender, rectiradiate to slightly 


UPPER KIMMERIDGE CLAY OF DORSET BG 


prorsiradiate. Outer whorl with similar style of ribs, remaining approximated but 
becoming a little coarser. Peristome with ventral horn 12~—15 mm. long. 


HoLotyre. Microconch C.73443. 
MATERIAL. Two specimens, both plaster casts, microconchs. 
Horizon. Holotype from 2r ft. below the White Stone Band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Hudlestoni Zone (upper part), 
18-21 ft. below the White Stone Band. 


DEscRIPTION. Large evolute shell with a diameter of 175-185 mm. Diameter 
of umbilicus 77-82 mm. The number of primary ribs on the last whorl is estimated 
as about 70. The holotype which is 175 mm. in diameter and which has an umbilical 
diameter of 77 mm. has at a diameter of 25 mm. 54 ribs; at 30,55; 35,57; 40, 573 
45, 59; 50, 60; 55, 62; 60, 62. (Text-fig. 6). The other specimen’s inner whorls 
are too poorly preserved to measure rib density. 

The ribs on the inner whorls are fine and slender. They are rursiradiate at the 
umbilical shoulder, then curve forwards to become straight and rectiradiate, or 
slightly prorsiradiate. The point of bifurcation of the ribs is high on the whorl-side. 
The umbilical seam uncoils over the last half whorl. 

The ribbing on the outer whorl is similar to that on the inner whorls. There is 
gradual coarsening of the ribs over the last whorl, but they are still approximated 
right up to the aperture. 

The peristome is straight and bears a horn r5 mm. long on the holotype. Two 
other horns are also visible on the last whorl of the holotype. These are 11 and 13 
mm. in length, and are ribbed. The other microconch specimen has three horns 
which in order of age are 6+; 19 and 12-++ mm. in length. 


Remarks. Members of this species include the largest known horned microconchs. 
It is interesting to note that the ribs on the last whorl differ very little in style and 
density from those of the earlier whorls. It seems probable that several of the larger 
species of the subgenus Virgatosphinctoides, of which no microconchs have been 
found hitherto, have microconchs similar in size to those of P. (V.) magnismasculus. 

Associated with the two microconch specimens was found a fragment of a large 
macroconch, which if complete would have had a diameter of about 320 mm. Its 
fragmentary nature and extremely poor preservation are such, however, that it 
cannot be referred to this species with any certainty. 


Pectinatites (Virgatosphinctoides) encombensis sp. nov. 


(Rie27 ties Pl 28) 

Dracnosis. Microconchs 70-103 mm. in diameter with following rib densities: 
at 20 mm. diameter there are 42-43 ribs; at 25, 43-47; 30, 44-49; 35, 46-52. Ribs 
of inner whorls very slender, rectiradiate to slightly prorsiradiate. Ribs on outer 
whorl gradually becoming a little more widely spaced, with abundant polygyrate 
furcation on body-chamber. Peristome with ventral horn 9-15 mm. in length. 
Macroconchs 155~215 mm. in diameter with following very approximate rib densities : 


58 UPPER KIMMERIDGE CLAY OF DORSET 


at 55 mm. diameter there are 52 ribs; at 60, 54; 65, 56; 70, 57; 75, 58; 80, 59; 
85, 60; 90, 61; 95, 63; I00, 64; 105, 65; 110, 66; 115, 67. Ribs of inner whorls 
similar to microconch. Outer whorl developing strengthened primary ribs becoming 
more widely spaced with occasional simple and polygyrate ribs and intercalatory 
secondaries. 


HoLotyPe. Microconch, C.73444. 
PARATYPE (ALLOTYPE). Macroconch C.73445. 


MATERIAL. Ten specimens, all plaster casts (three macroconchs, seven micro- 
conchs). 


Horizon. Holotype from 21 ft. and paratype from 33 ft. below the White Stone 
Band. 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Hudlestoni Zone (upper part), 
9-33 ft. below the White Stone Band. 


DeEscripTION. The holotype is a microconch, since no really adequately preserved 
macroconchs have been discovered. 

Microconch. Evolute shell with a diameter of 70-103 mm. Diameter of the 
umbilicus 28-38 mm. The holotype has a diameter of 103 mm. and an umbilical 
diameter of 38 mm. There are 63 primary and approximately 133 secondary ribs on 
the last whorl of the holotype. 

At 20 mm. diameter there are 43 ribs, at 25, 47; 30, 48; 35, 49. The variation in 
rib density is shown in Text-fig. 6. 

On the inner whorls the ribs are very slender. They are rursiradiate at the um- 
bilical shoulder, then bend forwards to become fairly straight and rectiradiate or 
slightly prorsiradiate. The umbilical seam uncoils over the last half whorl. 

The outer whorl is similarly ribbed, but gradually the ribs become a little more 
widely spaced and a little thicker. Abundant polygyrate ribs are developed on the 
last half whorl which appears to correspond to the length of the body-chamber. 

The peristome is fairly straight and bears a ventral horn which varies in length 
from 11-20 mm. The holotype and two other specimens have additional horns a 
little way back from the peristome. The holotype has a total of three horns which 
(in order of age) are 15, 15 plus and 11 mm. long. 

Macroconch. Evolute shell with a diameter of 155-215 mm. Diameter of 
umbilicus 75-118 mm. The paratype is the only macroconch showing any detail 
of the inner whorls. It is 215 mm. in diameter and has an umbilical diameter of 
118mm. There are approximately 68 primary and 122 secondary ribs on the last 
whorl. At55 mm. diameter there are an estimated 52 ribs; at 60, est. 54; 65, est. 56; 
70, €St. 57 75, est: 58 80, est. 59: 85; est: G0: 190; eSt. 61; 95, Est. 63> TOO,est.04; 
105, est. 65; 110, est, 66; 3125, est: 67. (Text-fig: 6). 

The ribs on the inner whorls appear to be of a style similar to those of the micro- 
conch; on the last umbilical whorl they appear straight and rectiradiate throughout 
their length. On the last half whorl the primary ribs become more widely spaced 
and prominent, and their furcation becomes irregular. Several polygyrate, simple 
and intercalatory ribs are developed. 


UPPER KIMMERIDGE CLAY OF DORSET 59 


The peristome is simple. 


REMARKS. Since the inner whorls are poorly preserved, the macroconch cannot 
be matched with the microconch as far as rib densities of the inner whorls go, but 
their association and similar sculpture strongly suggest that they are dimorphs of 
the same species. 

This species is distinguished from others by its rib style and density. It bears some 
resemblance to P. (V.) veisiformis described above (p. 50) in rib density, but the ribs 
themselves are considerably more slender in P. (V.) encombensis. The macroconchs 
are not so variocostate as those of P. (V.) ve1stformis, which provides another basis 
for distinction between these two species. 


Subgenus PECTINATITES Buckman 1922 


Synonyms. Wheatleyites Buckman 1923; Keyvatinites Buckman 1925; ? Pectiniformites 
Buckman 1925 (see p. 20). 


TYPE SPECIES. (By original designation). Ammonites pectinatus Phillips 1871. 


Diacnosis. Dimorphic. Microconchs generally finely ribbed on inner whorls, 
body-chamber usually more coarsely ribbed. Peristome with ventral horn often of 
great length. Macroconchs generally finely ribbed on inner whorls. Outer whorls 
variable, primary ribs typically strong with variable number of secondary ribs. 
Never truly virgatotome. Both macroconch and microconch show tendency for 
ribs to bifurcate very low on whorl side. Constrictions generally absent. 

Upper Kimmeridgian, ?Wheatleyensis Zone, Pectinatus Zone. 

Ammonites pectinatus Phillips was the first species, now included in this genus, 
to be described. Phillips’ figure (1871, pl. 15, fig. 77) is very poor, and the holotype 
has been long thought to have been lost. Arkell (1956 : 780) therefore designated a 
topotype as the neotype. 


Pectinatites (Pectinatites) inconsuetus sp. nov. 


(Pl. 30) 

Diacnosis. Macroconchs approximately 150 mm. in diameter. Ribs on outer 
whorl bifurcate low on whorl side. Ornamentation gradually fading on body- 
chamber. Peristome straight. Microconchs approximately roo mm. in diameter. 
At 50 mm. diameter there are approximately 50 ribs. Point of bifurcation of ribs 
becoming gradually lower on whorl-side towards last whorl. Body-chamber more 
coarsely ribbed than inner whorls. Peristome bearing short ventral horn. 


HoLotyrPe. Macroconch C.73446. 
PARATYPE (ALLOTYPE). Microconch C.73447. 
MATERIAL. Two specimens, both plaster casts (one macroconch, one microconch. 


Horizon. Both specimens from ro ft. above the Middle White Stone Band. 
Upper Kimmeridgian, lower Pectinatus Zone. 


60 UPPER KIMMERIDGE CLAY OF DORSET 


DESCRIPTION. Macroconch. Evolute shell witha diameter of 153mm. Diameter 
of umbilicus 65 mm. There are 26 primary and approximately 83 secondary ribs 
on the last whorl. 

The ribs on the inner whorls are not well preserved, but are seen to be rursiradiate 
at the umbilical shoulder, then swinging forwards to become straight and slightly 
prorsiradiate. The primary ribs on the outer whorl at first become more pronounced 
and are more widely spaced. They branch very low on the whorl-side, giving rise 
to up to four secondary ribs. There are abundant intercalatory secondary ribs, 
which also arise very low on the whorl-side. 

Over the last quarter of a whorl, the ribs gradually fade and become very indistinct. 

The peristome which is straight and simple inclines anteriorly towards the venter. 


Microconch. "Evolute shell with a diameter of 98 mm. Diameter of the umbilicus 
32mm. There are 50 primary and an estimated 110 secondary ribs on the last whorl. 
There are approximately 50 ribs at a diameter of 30 mm. 

The ribs on the inner whorls are fine and slender. They are rursiradiate 
at the umbilical shoulder, then curve forwards to become rectiradiate or slightly 
prorsiradiate. The point of bifurcation of the ribs is high on the whorl-side. 

The umbilical seam uncoils over the last half whorl. 

The ribs on the outer whorl are similar in style to those of the inner whorls, but 
gradually the point of bifurcation of the ribs becomes much lower on the whorl-side. 
Over the last half-whorl the primary ribs become stronger and more widely spaced, 
and usually give rise to three secondary ribs on the whorl-side. There are several 
simple and intercalatory ribs on the last half whorl. 

The peristome bears a horn. On the paratype this is broken, and the resultant 
broken end has not reproduced well in the plaster. The basal 4 mm. of the horn 
are just visible, however. 


REMARKS. [| earlier referred the macroconch of this species to the Tithonian genus 
Pseudovirgatites (Cope & Zeiss 1964 : 12). At the time of making this identification, 
however, the microconch had not been discovered. The style of ribbing of the macro- 
conch is very similar to some specimens of Pseudovirgatites from Franconia. How- 
ever, the microconch, with its broadly similar ribbing on its body-chamber and 
horned peristome, shows that this species belongs to the genus Pectinatites. 

This again is an example of the remarkable homeomorphy between the Tithonian 
and Upper Kimmeridgian ammonites which has misled so many workers in the past. 
This species of Pectimatites with its type of modification of the ribbing on the body- 
chamber of the macroconch is unlikely to be confused with any other species. 


Pectinatites (Pectinatites) eastlecottensis (Salfeld) 
(BIRZ6, fie) 


1913 Pevrisphinctes eastlecottensis Salfeld : 429, pls. 41, 42. 
1914 Perisphinctes eastlecottensis Salfeld ; Salfeld : 130. 
1922 Wheatleyites eastlecottensis (Salfeld) Buckman : 28. 
1923 Pectinatites aulacophorus Buckman, pl. 381. 

1925 Wheatleyites eastlecottensis (Salfeld) ; Neaverson : 37. 
1933 Pectinatites eastlecottensis (Salfeld) Arkell : 457. 


UPPER KIMMERIDGE CLAY OF DORSET 61 


MATERIAL. Two specimens, plaster casts (both microconchs). 


Horizon. Ten feet above the Middle White Stone Band. Upper Kimmeridgian, 
lower Pectinatus Zone. 


DescripTion. Neither of the two specimens from Kimmeridge is complete. 
The more complete of the two (C.73449, Pl. 26, fig. 1) has a diameter of 70 mm. and 
an umbilical diameter of approximately 22 mm. On the last half whorl preserved 
there are an estimated 58 primary and 97 secondary ribs. This would mean that ata 
diameter of 70 mm. there are about 100 ribs on a complete whorl. 

The holotype, which is a macroconch, has 130 ribs at r10 mm. diameter. The 
holotype of P. aulacophorus Buckman has (according to Buckman) about 97 ribs at 
66 mm. diameter. 

The noticeable feature on the Dorset specimens is that the ribs often bifurcate 
very close to the umbilical shoulder. 

The peristome is not preserved on either of the Dorset specimens but was probably 
originally horned. 


REMARKS. The extremely dense ribbing of this species is very characteristic. 
There can be little doubt that these Dorset specimens are the microconch of Salfeld’s 
figured macroconch. 

The holotype was quoted by Salfeld as coming from the Upper Lydite Bed at 
Swindon. Chatwin & Pringle (1921 : 166) later showed that in fact it came from 
the upper part of the Shotover Grit Sands. Buckman’s species P. aulacophorus was 
quoted by him as occurring in his Bed 12 at Swindon—the bed which yielded the holo- 
type of P. eastlecottensis. 

Buckman’s figure shows that the last sutures of P. aulacophorus are somewhat 
approximated, and that the umbilical seam is just beginning to uncoil. In this case 
it would appear that only the body-chamber is missing from this specimen, and it is, 
therefore, a microconch. Neaverson’s figure (1925, pl. I, fig. 5) of P. aulacophorus 
is an immature specimen of a species of the subgenus Virgatosphinctoides close to 
P. (V.) wheatleyensis delicatulus. 

The occurrence of this species in Dorset enables good correlations to be made with 
Swindon and Oxford. 


Pectinatites (Pectinatites) cf. groenlandicus (Spath) 


(Pal, Bie) 
1936 6©Pectinatites (Kervatinites?) groenlandicus Spath : 25, pl. 6, fig. 1. 

MATERIAL. One specimen (macroconch). 

Horizon. Ten feet above the Middle White Stone Band. Upper Kimmeridgian, 
lower Pectinatus Zone. 

DEscrRIPTION. The single incomplete specimen from Kimmeridge has a crushed 
diameter of 380 mm. Diameter of umbilicus 177 mm. At 40 mm. diameter there 
are 48 ribs; at 50, 53; 60, 70, 80, 90, 51; 100, 52; I10, 120, 53; 130, 54; 140, 55; 
150, 54; 160, 53; 170, 52. 


62 UPPER KIMMERIDGE CLAY OF DORSET 


There is a very close comparison between the Dorset specimen and the holotype 
which is from the Pectinatus Zone of Greenland. The furcation and style of the 
ribs on the inner whorls is very similar to that of the holotype (Spath, pl. 7, fig. 5). 
The point of bifurcation is very high on the whorl-side. | The outer whorl is similar, 
too, with the ribs becoming less prominent towards the aperture of the shell. The 
peristome, which is not preserved, is presumably simple. 


REMARKS. “ Wheatleyites”’ reductus (Buckman) (1923, pl. 384) shows certain 
similarities to this species, but the inner whorls of this species are more sharply and 
densely ribbed. 


Pectinatites (Pectinatites) cornutifer (Buckman) 


(Pl. 25, fig. 3; Pl. 26, fig. 2) 
1925 Kevratinites corvnutifey Buckman: pl. 602. 
1926 Kevatinites nasutus Buckman : pl. 664. 


MATERIAL. Eight specimens (all microconchs). 


STRATIGRAPHICAL RANGE. Upper Kimmeridgian, Pectinatus Zone (middle part), 
from 19 ft. below, to 6 ft. above the Freshwater Steps Stone Band. 


Description. Mucroconch. Moderately evolute shell with a diameter of 68-90 
mm. Diameter of the umbilicus 22-30 mm. There is good agreement with Buck- 
man’s figures in allrespects. The horn is long and varies from 15 to 39 mm. in length. 

No macroconchs have been found at this horizon in Dorset (see below). 


RemMARKS. K. cornutifer Buckman is finer ribbed than K. nasutus Buckman. 
However, there is a complete transition in the Dorset specimens between these two 
forms. The cornutifer type occurs in the lower part, and the nasutus type in the 
upper part of the range of this species in Dorset. In the almost complete absence of 
macroconchs in collections from this horizon in Dorset, it is not possible to refer 
this species to one of the known macroconch species of Pectinatites. P. pectinatus 
(Phillips) occurs together with this species at Swindon and in the Oxford region, so 
that it may well be the macroconch of P. cornutifer. 


Pectinatites (Pectinatites) naso (Buckman) 


(Bis32) 
1926 Kevatimites naso Buckman, pl. 652. 

MATERIAL. Three specimens, all plaster casts, (two macroconchs, one microconch). 

Horizon. Ten feet above the Freshwater Steps Stone Band. Upper Kimmerid- 
gian, middle Pectinatus Zone. 

DESCRIPTION. Macroconch. Fairly evolute shell with a diameter of 130-138 mm 
The diameter of the umbilicus is 50-54 mm. __‘ The figured specimen (C.73452) which 
has a diameter of 138 mm. and an umbilical diameter of 54 mm. has 40 primary 
ribs on the last whorl. At 25 mm. diameter there are about 45 ribs; at 30, 46; 35, 
47; 40,49; 45,47; 59, 45. 


UPPER KIMMERIDGE CLAY OF DORSET 63 


The ribs on the inner whorls are rectiradiate at the umbilical shoulder, then curve 
forwards to become quite strongly prorsiradiate. The point of bifurcation of the 
ribs is high on the whorl-side. 

On the outer whorl, just over half of which is preserved on the figured specimen, 
the primary ribs become stronger and more widely spaced. They branch fairly low 
on the whorl-side, giving rise to two or three secondary ribs. There are very 
occasional simple and intercalatory ribs. 

The peristome is simple. 

Microconch. The microconch (C .73453) is very similar to those figured by Buckman 
(pls. 652, 6522). 

The Dorset specimen is 91 mm. in diameter, and has an umbilical diameter of 31 
mm. There are an estimated 47 primary ribs on the last whorl. The preservation of 
the inner whorls is not good, and the following rib densities are only approximate: 
at 20 mm. 42 ribs; 25, 44; 30, 44. 

The ribs on the inner whorls are similar in style to those of the macroconch. The 
umbilical seam uncoils over the last half whorl. On the outer whorl the ribs become 
rather suddenly more coarse half a whorl from the aperture. This last half whorl 
appears to correspond to the length of the body-chamber (to judge by differences in 
the degree of crushing). Buckman’s specimens, too, have a body-chamber half a 
whorl in length. 

On the last half whorl the primary ribs become more widely spaced; their point 
of furcation is lower on the whorl-side than on the inner whorls, and the angle of 
furcation increases. Most of the ribs on the body-chamber are bifurcate, but there 
are occasional unbranched primary ribs. 

The peristome bears a horn which is 21 mm. long. 


Remarks. This species is readily distinguishable from P. cornutifer described 
above by the more coarsely ribbed body-chamber of the microconch. 

The macroconch is considerably more coarsely ribbed than the macroconch of 
P. pectinatus. 


Subfamily DORSOPLANITINAE Arkell 1950 


Genus PAVLOVIA Ilovaisky 1917 
Subgenus PARAVIRGATITES Buckman 1922 
Pavlovia (Paravirgatites) cf. paravirgatus (Buckman) 
(E33) 
1922 Pavavirgatites pavavirgatus Buckman, pl. 353. 
MATERIAL. One specimen C.73454. 


Horizon. Ten feet above the Freshwater Steps Stone Band. Upper Kim- 
meridgian, Pectinatus Zone (middle part). 

DESCRIPTION. The single poorly preserved specimen has a diameter of 146 mm. 
and an umbilical diameter of 66 mm. There are 28 primary and an estimated 55 
secondary ribs on the last whorl. 


64 UPPER KIMMERIDGE CLAY OF DORSET 


REMARKS. The specimen agrees closely with Buckman’s figure in all respects 
except size. The holotype is about 220 mm. diameter. The general similarity and 
the similar horizon (Shotover Grit Sands) leave little doubt of the affinities of the 
Dorset specimen to Buckman’s holotype. 


Ve EVOLULLION OF DEE AVVO Nis: 


The possible origin of the genus Pectimatites from an ataxioceratid stock has been 
discussed earlier (p. 22). Within the genus three subgenera are recognized and it is 
possible to follow in these subgenera various evolutionary trends. 

The subgenus Arkellites first appears at the base of the Elegans Zone where it is 
represented by specimens referable to P. (A.) primutivus. Arkellites is characterized 
by more or less equicostate ribbing of the shell. This feature appears in the four 
species of the subgenus hitherto described. The macroconchs remain basically 
similar in rib style and ornamentation throughout the succession. In the micro- 
conchs, however, the tendency is for the horn to become much more prominent. P. 
(A.) primitivus has a weak ventral peristomal inflation, but all the later species have 
a well-developed true horn. The youngest species of Arkellites hitherto recorded, 
P. (A.) hudlestoni, shows a general similarity to these earlier species, and the conclu- 
sion is drawn that this subgenus was a fairly conservative one. There are as yet no 
species recorded from the Wheatleyensis Zone which can with certainty be placed 
in this subgenus, so that the connection between P. (A.) hudlestoni and earlier species 
of the subgenus is not known. However, Paravirgatites kimmeridgensis Neaverson 
(1925 : 33, pl. 4, fig. 4) has a rib density on its inner whorls close to that of P. (A.) 
hudlestom, and may belong to this subgenus. The author cannot accept Neaverson’s 
placing of his species in Buckman’s genus Paravirgatites. The holotype shows the 
rib style, rib density and development typical of Avkellites, which 1s entirely different 
from the sharp regular bifurcate ribbing characteristic of the pavlovids. It is to be 
expected that the Wheatleyensis Zone will ultimately yield species which can 
definitely be assigned to the subgenus Arkellites. 

The subgenus Virgatosphinctoides which appears in Dorset about a third of the way 
up the Elegans Zone could have been derived from P. (A.) primitivus (see p. 33). 
Unlike Arkellites, from which it probably arose, Virgatosphinctotdes evolved rapidly. 
The horn of the microconch, represented by a ventral peristomal inflation in P. (V.) 
elegans, becomes a true horn by the top of the Elegans Zone (P. (V.) elegans corniger). 
Thereafter, the horn development becomes more pronounced, particularly in the 
Hudlestoni Zone. There are some species, however, (e.g. P. (V.) woodwardi) in 
which the horn development is not so pronounced. Considering next the macro- 
conchs, the tendency seen is for the degree of variocostation of the shell to become 
more pronounced. Associated with this is the increase in the numbers of polygyrate 
ribs on the body-chamber. This trend continues with the appearance of virgatotome 
ribbing in the Wheatleyensis Zone. Some later forms from the Hudlestoni Zone 
(e.g. P. (V.) donovanz) show, to some extent, a reversal of this trend, and the loss of 
the truly virgatotome rib type. 


UPPER KIMMERIDGE CLAY OF DORSET 65 


ELEGANS 


GEOL. I5, I. 


PRIMITIVUS — —_ 


= 
Ww 
= 
< 
NASO 
z CORNUTIFER— 
Re 
INCONSUE TUS 
nt eae GROENLANDICUS 
a EASTLECOTTENSIS = ie 6 
\—_ PECTINATITE? 
| 
ENCOMBENSIS 
| 
Z | 
ie | 
Ww | 
B 2 G/ MAGNIMASCULUS | 
= My & DONOVANI 
= Tes TONY & | R. DENSICOSTATUS Se 
ly SS | 
x< aN Ss 
ra | ABBREVIATUS 
= GrACCELERATUS ea ene I 
| 
W. DELICATULUS 
Ww 
D | 
G | WHEATLEYENSIS 
7 GRANDIS WOODWARDI 
at W. MINOR 
= LATICOSTATUS 
. PSEUDOSCRUPOSUS ss 
z SMEDMORENS/S 
CLAVELLI 
| 
Ww 
= DAMON! 
= SCITULUS 
O 
a DECOROSUS 
ea 7 
CUDDLENS/S E. CORNIGER 


ELEGANS 


TECH toy 


Possible phylogenetic relationships of species of Pectinatites. 


66 UPPER KIMMERIDGE CLAY OF DORSET 


The origins of the subgenus Pectinatites are almost certainly to be found in the 
subgenus Virgatosphinctoides. However, the actual point of origin is not clear. 
Pectinatites may be derived from such a form as P. (V.) encombensis, which has a 
finely ribbed shell, a microconch with a well-developed horn, and an absence of 
virgatotome ribs on the macroconch. Alternatively, the subgenus may have been 
derived from Virgatosphinctoides earlier, perhaps as early as the Wheatleyensis Zone. 
In Pectinatites the main trends observed, as far as the lower part of the Pectinatus 
Zone goes, appear to be the tendency for the ribs to bifurcate low on the whorl-side, 
and for the microconch horn to increase in length, reaching almost 40 mm. in P. (P.) 
cornutifer. 

Homeomorphy occurs within the genus Pectinatites, particularly between species 
of the subgenera Virgatosphinctoides and Pectinatites. However, the homeomorphy 
always seems to appear in only one sex, and not in both sexes together. 

Text-fig. 8 shows diagrammatically the possible relationships between the known 
species of the genus. It is not, of course, to be expected that this can represent an 
entirely complete picture. In particular, knowledge is scant at the base of the 
Elegans Zone, the upper part of the Scitulus Zone, and the lowermost Pectinatus 
Zone. 


VI. THE AMMONITE ZONES 


As a result of detailed collecting from the Kimmeridge section, the position of 
several species of ammonites, described from other areas, has been established for 
the first time. This has necessitated considerable modification of the existing table 
of zones (see Text-fig. 9). 

Since the range of many species is known fairly accurately, it is proposed to set up 
a sub-zonal scheme, should this prove possible, at a future date. As a prerequisite 
for this, however, detailed knowledge of the ammonite faunas over a large area is 
considered necessary. Unfortunately the Oxford and Swindon areas, which could 
have yielded much from careful collecting, are now devoid of good, or even adequate, 
exposures of Upper Kimmeridge Clay. The sections in Yorkshire and Sutherland 
may, however, provide good information, particularly on the lower zones. 

At this time, therefore, no further refinement than zonal subdivision is attempted. 


Pectinatites (Virgatosphinctoides) elegans Zone 


INDEX SPECIES. Pectinatites (Virgatosphinctoides) elegans. 

This new zone is proposed for the beds between the thin cementstone band (Bed 
no. 42) and the Yellow Ledge Stone Band (Bed no. 36) of the Kimmeridge section. 

This new zonal index replaces a zone based on species of the genus Gravesta which 
were first used for zonal subdivision of the Kimmeridge Clay by Salfeld. After his 
discovery in Dorset of species of ammonites, for which he proposed the genus, he 
set up two zones, for the shales between the Maple Ledge Stone Band (Arkell 1947 : 73) 
and the Yellow Ledge Stone Band, with species of Gravesia as their index fossils. He 
proposed an upper zone of Gvavesia wius and a lower one of Gravesia gravesiana 
(Salfeld 1913). 


7 


¢ 


UPPER KIMMERIDGE CLAY OF DORSET 


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Zones of the lower part of the Upper Kimmeridge Clay. 


FiG. 9. 


68 UPPER KIMMERIDGE CLAY OF DORSET 


Salfeld did not draw any junction between these two zones, and the specific 
identity of his specimens has long been in doubt. Arkell (1947 : 76) reported that 
he had seen Salfeld’s specimens in Gottingen in 1937, but did not comment upon 
their identity. He called these two zones merely the Gravesia spp. zones (1947 : 67), 
and raised the lower limit of the zones in Dorset up to the unnamed cementstone band 
at the foot of Hen Cliff (about 65 ft. higher in the succession). 

Later Arkell (1956 : 21) divided these Hen Cliff shales into an upper Gravesia gigas 
Zone and a lower Gravesia gravesiana Zone. Again, no boundary between these 
zones was fixed. 

Arkell’s raising of the upper limit of the Awlacostepbhanus Zones is justified by the 
occurrence of this genus up to about 15 ft. below the thin cementstone band referred 
to above. This band also marks the first appearance of specimens of Pectinatites 
(Arkellites), which are fragmentary and poorly preserved, but are probably close to 
P. (A.) primitivus. 

The genus Gravesia is exceptionally rare in Dorset, and since 1913 only seven speci- 
mens of the genus have been found (three by Spath, two of which are in the British 
Museum, and one in the Geological Survey Museum; and four by the author). 
Of these ammonites, five are specimens of Gravesia gigas and have been found between 
40 and 52 ft. below the Yellow Ledge Stone Band. The other two are referred to 
Gravesia gravesiana and came from eight feet below and six feet above the Yellow 
Ledge Stone Band (i.e. higher than any previously recorded specimens). No known 
Gravesia irius has been found since Salfeld’s report of its abundant occurrence in 1913. 

Whether or not Gravesia irius does in fact occur at Kimmeridge, it is clear that 
Gravesia gravesiana is restricted to beds higher than those yielding Gravesia gigas 

It is thus proposed to set up this zone based on a species of Pectinatites, since 
species of this genus are common in these beds in Dorset. This obviates any diffi- 
culty over fixing of boundaries of zones based on extremely rare index fossils, and 
since species of Pectinatites occur in this zone in Yorkshire (whereas Gravesia does not) 
there should in future be no ambiguity as in the past. 

The base of the zone is fixed above the highest occurrence of Awlacostephanus, 
and at the earliest occurrence of Pectinatites. P. (Arkellites) primitivus occurs from 
the base of the zone into the upper part. P. (V.) elegans appears below the middle of 
the zone and ranges into the upper part, where it is replaced by P. (V.) elegans 
cormger. P. (Arkellites) cuddlensis occurs in the top 18 ft. of the zone. The top of 
the zone corresponds to the highest occurrence of P. (V.) elegans corniger. Gravesia 
gigas occurs just below the middle of the zone, G. gravesiana ranges from the highest 
part of the zone into the base of the succeeding Scitulus Zone. 


Pectinatites (Virgatosphinctoides) scitulus Zone 


INDEX SPECIES. Pectinatites (Virgatosphinctoides) scitulus sp. nov. 

This new zone is proposed for the shales between the Yellow Ledge Stone Band 
and the Grey Ledge Stone Band in the Dorset succession. This thickness of go ft. 
includes the Lower Cattle Ledge Shales (up to Cattle Ledge), and the Upper Cattle 
Ledge Shales (between Cattle Ledge and Grey Ledge). 


PEC TINATUS 


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z Zam 
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Pectinatites ( Pectinatites) inconsuetus 
A 


P(P) naso 
4 


P(P) cornutifer 
4 


P(P) groenlandicus 
H 


P(P) eastlecottensis 


Paviovia (Paravirgatites) paravirgatus 


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Pectinatites (Virgatosphinctoides) smedmorensis 


HEATLEYENSIS 


P(P) groenlandicus 
H 


RCV.) wheatleyensis minor, 
P(R) eastlecottensis 


----------d 


UPPER KIMMERIDGE CLAY OF DORSET 69 


The Upper Cattle Ledge Shales have hitherto failed to yield ammonites and are 
provisionally included in this zone, pending ammonite evidence from Dorset or 
elsewhere. 

Pectinatites (Virgatosphinctoides) scitulus first appears at the base of the zone, and 
ranges to about the middle of the ammonite bearing strata. Gvravesia gravesiana 
occurs in the lowest six feet of the zone at Kimmeridge. Exogyra virgula ranges up 
to 27 ft. above the Yellow Ledge Stone Band. Lingula ovalis reaches its maximum 
abundance near the base of the zone. 

This zone corresponds to the lower part of Salfeld’s Virgatites miatschkovensis 
Zone, the lower part of Neaverson’s Virgatosphinctoides wheatleyensis Zone, and the 
Subplamites ? vimineus Zone of Spath (Arkell 1956 : 21). 


Pectinatites (Virgatosphinctoides) wheatleyensis Zone 


INDEX SPECIES. Pectinatites (Virgatosphinctoides) wheatleyensis (Neaverson). 

This zone, which in the Dorset succession is represented by the beds between the 
Grey Ledge Stone Band and the Rope Lake Head Stone Band, corresponds to part 
of the Virgatites miatschkovensis Zone of Salfeld (1913); the Pseuwdovirgatites Zone of 
Lamplugh, Kitchin & Pringle (1922); the lower part of the Pectinatus, the Nodiferus 
and the upper part of the Wheatleyensis Zone of Neaverson (1925); and to all but 
the uppermost part of the Grandis Zone of Arkell (1956). 

The position of Pectinatites (Virgatosphinctoides) wheatleyensis (Neaverson) has 
hitherto been very uncertain in the Dorset succession. In Oxfordshire, it occurs 
associated with P. (V.) woodwardi, P. (V.) wheatleyensis delicatulus and Sphinctoceras. 
The same faunal association (without Sphinctoceras), but with P. (V.) grandis and 
P. (V.) pseudoscruposus in addition, is found in Dorset in the shales immediately 
below the Blackstone. 

At the base of the zone ammonites of the subgenus Virgatosphinctoides are repre- 
sented by P. (V.) clavelli, P. (V.) smedmorensis and P. (V.) laticostatus; the latter 
two species ranging up to the middle of the zone. 

The crinoid Saccocoma ranges in Dorset through 13 ft. of Beds in the upper part of 
the Zone. 

The top of the Zone corresponds to the highest occurrence of P. (V.) wheatleyensis 
delicatulus and the earliest occurrence of P. (V.) reisiformis. 

The zone is represented in the Oxford district by the Wheatley Nodule Bed, and is 
present on the Yorkshire coast. 


Pectinatites (Arkellites) hudlestoni Zone 


INDEX SPECIES: Pectinatites (Arkellites) hudlestoni sp. nov. 

This new zone is proposed for the beds between the Rope Lake Head Stone Band 
and the White Band in the Kimmeridge succession. It corresponds to the upper 
part of Salfeld’s Virgatites miatschkovensis Zone, part of Neaverson’s Pectinatus 
Zone, and to the Wheatleyensis Zone and topmost part of the Grandis Zone of 
Arkell. At the base of the zone Pectinatites (Virgatosphinctoides) reisiformis occurs, 
and a little above the base is associated with P. (A.) hudlestoni which ranges through- 


70 UPPER KIMMERIDGE CLAY OF DORSET 


out the zone. The middle part of the zone is characterized by P. (V.) donovani 
and the upper part by P. (A.) hudlestont, P. (V.) encombensis and P. (V.) magnimas- 
culus. 

Inland this zone may be represented by the Shotover Fine Sands and the Lower 
Cemetery Beds in the Oxford and Swindon areas respectively. There is no palaeonto- 
logical evidence to support this correlation directly, however, and the zone, if present 
is certainly very much attenuated. It is probably present in Yorkshire. 


Pectinatites (Pectinatites) pectinatus Zone 


INDEX SPECIES. Pectinatites (Pectinatites) pectinatus (Phillips). 

This zone corresponds to the Perisphinctes pallasianus Zone of Salfeld, the upper 
part of the Pectinatus Zone of Neaverson, and the Pectinatus Zone of Arkell. 

In Dorset the lower boundary of the zone is taken at the White Stone Band which 
marks the upper limit of the range of the subgenus Virgatosphinctoides, and the upper 
boundary below the first occurrence of Pavlovia s.s. The upper part of this zone has 
not yet been fully investigated in Dorset. 

The earliest species recorded in Dorset is Pectinatites (Pectinatites) eastlecottensis ; 
this species is recorded together with such species as P. (P.) cornutifer and P. (P.) naso 
from the Shotover Grit Sands in the Oxford region. No detailed stratigraphical 
collections have been made from these beds in the Oxford region, however, and it 
may be that they are not in fact completely synchronous, as published faunal lists 
suggest. In Dorset there is little overlap of the ranges of these species (Text-fig. 10), 
and it is to be expected that detailed collecting would show similar relationships 
between the various ranges of species in the Oxford area, where the succession is 
considerably thinner. 


VIII. CORRELATIONS 


(a) GREAT BRITAIN 


The Upper Kimmeridge Clay is exposed in only a limited number of localities in 
Britain, and of these few exposures most are now very poor. The majority of the 
published faunal lists from these exposures are now outdated, and nowhere have 
collections been made in detail comparable to that recently carried out in Dorset. 
For these reasons, correlations with other areas of Britain cannot, in most cases, be 
established with a great deal of accuracy at present. It is hoped that future collecting 
will remedy this deficiency. 

Two areas of Britain where the succession of the Kimmeridgian faunas have been 
well known for some time are the Swindon and Oxford regions. Correlations with 
these areas are shown in Text-fig. 11. In both these areas the succession is consider- 
ably attenuated. The ammonites, however, are generally better preserved than 
those in Dorset and have therefore attracted considerably more attention in the past. 
It was primarily on information obtained from the Oxford area that Neaverson (1925) 
set up his zonal scheme for the Upper Kimmeridge Clay. It is now possible for the 
first time to show the true stratigraphical position of many of Neaverson’s species in 
the complete Dorset succession, As a direct result of this, it appears likely that there 


71 


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KIMMERIDGE CLAY 


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Correlation of the lower part of the Upper Kimmeridge Clay of Kimmeridge 


TRAC 


Fic. 


with that of the Swindon and Oxford areas, 


WP UPPER KIMMERIDGE CLAY OF DORSET 


is a previously undetected non-sequence in both the Oxford and Swindon areas, 
between the Pectinatus and Wheatleyensis Zones, corresponding to the Hudlestoni 
Zone. This zone may be represented in part, however, by the Shotover Fine Sands. 

Between the Lower and Upper Kimmeridge Clay there is a major non-sequence 
in the Oxford area. Above the Aulacostephanus Zones are beds yielding Pectinatites 
(Virgatosphinctoides) wheatleyensis. There are no known records of fossils indicative 
of the Elegans or Scitulus Zones. At Swindon, however, the position is different. 
Chatwin & Pringle (1922 : 165) mention that the Hudleston collection contains a 
specimen of Gvavesia from Swindon, and it is therefore possible that the succession in 
this region, though attenuated, is fairly complete. 

In Yorkshire the Kimmeridge Clay is exposed beneath the Lower Cretaceous rocks 
which rest unconformably on it at Speeton. The Kimmeridge Clay here is little 
known palaeontologically. The highest horizon recorded in this section is the 
Wheatleyensis Zone, but a specimen sent to me by Dr. P. Kaye from the highest beds 
of the Kimmeridge Clay, is undoubtedly close to Pectinatites (P.) proboscide (Buck- 
man), requiring correlation with the Pectinatus Zone. There appears no reason to 
believe that the Yorkshire succession is not complete up to this latter zone. The 
Elegans Zone in Yorkshire is unlikely to yield Gvavesia since the presence of this 
genus has not been confirmed north of Swindon. 

In Sutherland, the lowest part of the Upper Kimmeridge Clay appears to be present, 
to judge from the account by Bailey & Weir (1932). Above the Aulacostephanus 
zones they recorded species of Lithacoceras indicative of the Gravesia zones, and 
evidence for the lower part of the Vivgatites zone. I interpret this evidence as 
showing that the Elegans and possibly Scitulus Zones are present. The record of 
Lithacoceras presumably refers to a species of Pectinatites perhaps of the Elegans Zone. 
This area is one from which collecting is planned in the future. 


(b) THE BOULONNAIS 


The Upper Kimmeridgian of the Boulonnais shows similarities to the Kimmeridgiau 
of Britain. It is remarkable chiefly for the development of phosphatic nodule beds 
at several horizons. The succession below is based on descriptions by Pruvost (1924), 
with modifications after Arkell (1956 : 42) and revised determinations of the 
ammonite names. 


Bed. No. (Pruvost) 1924) 


Ph. 3. Tour Croi Nodule Bed with phosphatized ammonites: 
Pavlova rotunda, P. leblondi, Pectinatites (Pectinatites) devillei, P. (P.) 
boidim, Pectinatites (P.) rarescens, P. (P.) opulentus. 

5. Clay 26 ft.: P. (P.) devillet, P. (P.) boidim, P. (P.) sp., Pavlovia lydianites, 
Exogyra dubiensis. 

Ph. 2. Phosphatic nodule Beds: undescribed ammonites: 

4. Clay 6 ft. 6 ins.: undescribed ammonites, Lingula ovalis, Discina latissima, 
Modiola autissiodorensis, Anomia laevigata. 


UPPER KIMMERIDGE CLAY OF DORSET 73 


Ph. r. La Rochette Nodule bed: Pectinatites (Virgatosphinctoides) pringlet, P. (V.) 
spp. 
Bs Clays 26 ft. Discina latissima, Pectinatites (Virgatosphinctotdes) spp. 
Gres de la Creche (upper part) 16 ft.: Pectinatites (Virgatosphinctotdes) sp. 
Gres de la Creche (lower part) 32 ft.6ins. Gvavesia portlandica (? =G. gigas), 
“ Perisphinctes’” bleicheri, Trigonia pellati, Exogyra virgula. 


she) 


Aulacostephanus Zones. 


Again the ammonite fauna of these beds is not well known, but on the basis of the 
recorded species and the associated fauna, several correlations may be suggested. 

Bed 1 corresponds to the Elegans Zone. Gyvavesia portlandica (de Loriol) is 
probably a junior synonym of G. gigas (Zieten). Trigonia pellati and Exogyra virgula 
also occur in this zone in Dorset. 

Beds 2-4 probably correspond to the Scitulus, Wheatleyensis and Hudlestoni Zones. 
Pectinatites (Virgatosphinctoides) pringle: (horizon Ph. 1) is close to P. (V.) wheat- 
leyensis, and is probably, therefore, from the mid-Wheatleyensis Zone. 

Bed 5 appears to correspond to the upper part of the Pectinatus Zone, and the 
Tour Croi Nodule Bed to the Rotundum Zone. 


(c) EAST GREENLAND (MILNE LAND) 


The Kimmeridgian fauna of Greenland were the subject of papers by Spath (1935, 
1936). He described therein collections made on expeditions led by Dr. Lauge Koch. 
The Upper Kimmeridgian succession there (Spath 1936 : 163) is: 


Pavlovia Beds. 150 ft. 
Pectinatites Beds. 150 ft. 
Unfossiliferous Shales. 120 ft. 
Band of crushed Perisphinctids. 


The Pectinatites Beds correspond to the Pectinatus Zone of Dorset. Specific 
identity is established with Dorset in two cases. 

The band of crushed Perisphinctids yielded three specimens which Spath identified 
tentatively as Swubdichotomoceras?, Subplanites? (Virgatosphinctoides?), and Sub- 
plamites? (Spath 1936, pl. 1). The latter two specimens appear from the plate to 
resemble forms from the Wheatleyensis Zone, and are probably to be correlated with 
this zone. The unfossiliferous beds between these two points of correlation probably 
representing the Hudlestoni Zone of Dorset. No fauna to be correlated with Elegans 
or Scitulus Zones is recorded from East Greenland. 


(d) SOUTHERN GERMANY (FRANCONIA) 


In the southern part of Europe the ammonite fauna of the Upper Jurassic rocks 
becomes markedly different from that of North-west Europe, above the Lower 
Kimmeridgian. To these rocks equivalent to the Upper Kimmeridgian and Port- 
landian Stages of North-west Europe the stage name “ Tithonian”’ is generally 
applied. 


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9S6l T14yNYV AG SNOILVISYYOD 


74 


(y96lL SSI3Z GNV 3dOD Y314V G3IlsIGdOW) 
SNOILV1SYeeOD GSLSa99NS 


Correlations between the Upper Kimmeridgian and Lower Portlandian of 


WZ, 


Fic, 


Britain, and the Lower Tithonian of Franconia. 


UPPER KIMMERIDGE CLAY OF DORSET 75 


The area taken herein, as representative of typical Tithonian rocks, is Franconia. 
I have recently visited this area, and have examined large ammonite collections made 
by Dr. A. Zeiss of the University of Erlangen, with whom I discussed problems of 
correlation between the two faunal provinces. The results of these discussions were 
incorporated in a joint paper (Cope & Zeiss 1964). 

The most firm bases for correlation are to be found between the basal and upper- 
most Upper Kimmeridgian and basal Portlandian, and their Franconian equivalents. 
In the Lower Neuberg Beds specimens of Pavlovia and Zaraiskites have recently 
been found. This gives good correlations with the uppermost Kimmeridgian and 
basal Portlandian of Dorset. The discoveries are particularly important since it 
means that the Kimmeridgian—Portlandian boundary can be traced into the Tithonian 
faunal province. 

At the base of the Upper Kimmeridgian the genus Grvavesia occurs, its vertical 
range in Dorset being about 60 ft. In Franconia, Gvavesia occurs in the Moernsheim 
Beds where its vertical range is about go ft. 

Between these two points where correlation can definitely be established, the 
faunas of the two provinces are distinct. In Britain species of Pectinatites are the 
commonest ammonites, and in Franconia species of Subplanites, Lithacoceras and 
Pseudovirgatites. As stated earlier (p. 20) Subplamites and Lithacoceras do not occur 
in Britain. It therefore appears that the apparent similarity between the two faunas 
is due entirely to the phenomenon of homeomorphy. 

It is remarkable to find that some homeomorphs seem to have existed contem- 
poraneously. Thus some ammonites of the Pectinatites (Virgatosphinctoides) grandis 
group are very close to undescribed ammonites from the Usseltal Beds. P. (Virgato- 
sphinctoides) reisiformis has a very similar microconch to Subplanites siliceus, the 
apertural modifications of the two forms being the only apparent point of difference. 
P. (Pectinatites) inconsuetus has a macroconch almost identical in appearance to an 
undescribed species of Pseudovirgatites. 

Such homeomorphs cannot provide correlations, but it has been found that their 
respective stratigraphical ranges are approximately equal in some cases. It appears 
that direct correlation by means of ammonites is not possible in this case, and the 
problem is unlikely to be solved until an area is discovered where an overlap of the 
faunal provinces occurs. 


(e) Russia (BASIN OF THE URAL AND ILEK RIVERS) 


The Upper Kimmeridgian faunas of the basin of the Ural and Ilek rivers were 
described by Ilovaisky & Florensky (1941). The specimens they described came 
from the Vetlianka Sandstone, and were described as belonging to the genus J/ovaiskya 
Vialov 1940. This genus was regarded by Arkell (1957) as a junior synonym of 
Subplanites Spath 1925. 

Although several of the forms figured by Ilovaisky & Florensky appear very similar 
to British species, and were identified as such by Arkell (1956 : 489-490), identity 
even at generic level with British forms cannot be established on the basis of the 
published plates, None of the ammonites figured by Hovaisky & Florensky has its 


76 UPPER KIMMERIDGE CLAY OF DORSET 


peristome preserved, and thus may belong equally to Subplanites or its homeomorph 
Pectinatites. As no specimens similar to Lithacoceras were figured, it is possible that 
the Russian forms belong to Pectinatites rather than to Subplanites. The collection 
of material with peristomes intact is essential, however, for this to be established 
with certainty. 

This problem has not been resolved in a more recent paper by Michailov (1964). 
He figures specimens under the names of Subplanites and Pectinatites. It may well 
be that in parts of Russia there is a mixture of these two faunal elements, but again 
the absence of peristome-bearing specimens means that such generic placings by 
Michailov may be incorrect. 


WAMIEIES IRIN ID IRIS INCE 13S 


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UPPER KIMMERIDGE CLAY OF DORSET 77 


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78 UPPER KIiMIME RT DIGE (Clay OF DOORS» fi 


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UPPER KIMMERIDGE CLAY OF DORSET 79 


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PLATES 
The photographs are by Mr. S. P. Osborn of the Geology Department, University 
College, Swansea. 
All the specimens were whitened with ammonium chloride prior to photographing. 


PLALE tr 
Fic. 1. Gravesia gigas (Zieten). C.73390, x 0-45, 45 feet below Yellow Ledge Stone Band. 


Fic. 2. Gravesia cf. gravesiana (d’Orbigny). C.73391, x1, 8 feet below Yellow Ledge Stone 
Band. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 IL NANI SS an 


GEOL, I5, I. 6 


PLATE 2 


Fic. 1. Pectinatites (Arkellites) primitivus sp. nov. Holotype (macroconch), C.73392, 
XI, 25 feet below Yellow Ledge Stone Band. 

Fic. 2. Pectinatites (Arkellites) primitivus sp. nov. Paratype (microconch), C.73395, 
XI, 55 feet below Yellow Ledge Stone Band. 

Fic. 3. Pectinatites (Arkellites) hudlestoni sp. nov. Microconch, C.73402, 1-5, ventral 
view showing possible points of shedding of horns. 13 feet above Rope Lake Head Stone Band. 


PEASE 2 


Bull. Br. Mus. nat. Hist. (Geol.) 


PLATE 3 


Fic. 1. Pectinatites (Arkellites) primitivus sp. nov. Paratype (macroconch), C.73393, 


XI, 25 feet below Yellow Ledge Stone Band. 
Fic. 2. Pectinatites (Arkellites) primitivus sp. nov. Paratype (microconch), C.73394, 


XI, 25 feet below Yellow Ledge Stone Band. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 PVA E, 3 


PLATE 4 


Pectinatites (Arkellites) cuddlensis sp. nov. Holotype (macroconch), C.73396, x1, 
18 feet above Yellow Ledge Stone Band. 


PLATE 4 


Bull. By. Mus. nat. Hist. (Geol.) 15, 1 


PL Adee 


Fic. 1. Pectinatites (Arkellites) cuddlensis sp. nov. Paratype (microconch), C.73397, 
XI, 25 feet above Yellow Ledge Stone Band. 

Fic. 2. Pectinatites (Arkellites) damoni sp. nov. Paratype (microconch), C.73400, x1, 
25 feet above Yellow Ledge Stone Band. 

Fic. 3. Pectinatites (Arkellites) damoni sp. nov. Paratype (microconch), C.73401, XI, 
25 feet above Yellow Ledge Stone Band. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 PIE JNIEID, & 


PLATE 6 
Fic. 1. Pectinatites (Arkellites) damoni sp. nov. Paratype (macroconch), C.73399, x1, 
27 feet above Yellow Ledge Stone Band. 
Fic. 2. Pectinatites (Arkellites) damoni sp. nov. Holotype (macroconch), C.73398, TI, 
25 feet above Yellow Ledge Stone Band. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 PLATE 6 


PLATE 7 


Pectinatites (Arkellites) hudlestoni sp. nov. Holotype (macroconch), C.73403, 0°85, 
13 feet above Rope Lake Head Stone Band. 


PLATE 7 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 


PLATE 8 


Fic. ta. Pectinatites (Virgatosphinctoides) elegans sp. nov. Paratype (microconch), 
C.73406, <1, 20 feet below Yellow Ledge Stone Band. 

Fic. tb. Reverse side of specimen in Fig. 1a, showing detail of the peristomal inflation. TI. 

Fic. 2. Pectinatites (Arkellites) hudlestoni sp. nov. Paratype (microconch), C.73404, 
XI, 13 feet above Rope Lake Head Stone Band. 


Bull. By. Mus. nat. Hist. (Geol.) 15, 1 RAEI NALD, (3) 


3 ; 
a » to 
" . a 
t mS, 
4 4 
: G 


% 


PLATE 9 


Pectinatites (Virgatosphinctoides) elegans sp. nov. Holotype (macroconch), C.73405, 
0:95, 18 feet below Yellow Ledge Stone Band. 


PLATE 9 


Bull. By. Mus. nat. Hist. (Geol.) 15, 1 


GEOL, I5, I. 


IPIEINIDIZ, s¢6) 


Fic. 1. Pectinatites (Virgatosphinctoides) elegans corniger subsp. nov. 


(macroconch), C.73407, x1, 5 feet below Yellow Ledge Stone Band. 


Fic. 2. Pectinatites (Virgatosphinctoides) elegans corniger subsp. nov. 


(microconch), C.73409, x1, 8 feet below Yellow Ledge Stone Band. 


Fic. 3. Pectinatites (Virgatosphinctoides) elegans corniger subsp. nov. 


(microconch), C.73408, x1, 5 feet below Yellow Ledge Stone Band. 


Holotype 


Paratype 
Paratype 


Bull. Bry. Mus. nat. Hist. (Geol.) 15, 1 PLATE 1o 


id 
y 4 


| \\ 


TIGA ALIS, ae ie 
Fic. 1. Pectinatites (Virgatosphinctoides) scitulus sp. nov. Holotype (macroconch), 
C.73411, x0°85, 24 feet above Yellow Ledge Stone Band. 
Fic. 2. Pectinatites (Virgatosphinctoides) scitulus sp. nov. Paratype (microconch), 
C.73412, 0°85, 25 feet above Yellow Ledge Stone Band. 
Fic. 3. Pectinatites (Virgatosphinctoides) scitulus sp. nov. Paratype (microconch), 
C.73413, X0:85, 15 feet above Yellow Ledge Stone Band. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 PYPACEE) 11 


PLATE 12 
Fic. 1. Pectinatites (Virgatosphinctoides) decorosus sp. nov. Holotype (macroconch), 
C.73414, XI, 15 feet above Yellow Ledge Stone Band. 
Fic. 2. Pectinatites (Virgatosphinctoides) decorosus sp. nov. Paratype (microconch), 
C.73415, X1, 15 feet above Yellow Ledge Stone Band. 


Bull. Bry. Mus. nat. Hist. (Geol.) 15, 1 PAGAN TE 2 


PLATE 13 


Pectinatites (Virgatosphinctoides) major sp. nov. Holotype (macroconch), C.73410, 
x 0-55, 6 feet below Yellow Ledge Stone Band. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 PACE 3 


PLATE 14 

Fic. 1. Pectinatites (Virgatosphinctoides) clavelli sp. nov. Holotype (macroconch), 
C.73432, x0-7, 8 feet above Grey Ledge Stone Band. 

Fic. 2. Pectinatites (Virgatosphinctoides) clavelli sp. nov. Paratype (microconch), 
C.73433, 0-7, 3 feet above Grey Ledge Stone Band. 

Fic. 3. Pectinatites (Virgatosphinctoides) clavelli sp. nov. Paratype (microconch), 
C.73434, X0-7, 3 feet above Grey Ledge Stone Band. 


PLATE 14 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 


PI AME 15 


Fic. 1. Pectinatites (Virgatosphinctoides) smedmorensis sp. noy. Holotype (macro- 
conch), C.73430, I, 22 feet below Blackstone. 

Fic. 2. Pectinatites (Virgatosphinctoides) smedmorensis sp. nov. Paratype (micro- 
conch), C.73431, I, 22 feet below Blackstone. The postulated original shell outline indicated 
by broken lines. 

Fic. 3. Pectinatites (Virgatosphinctoides) grandis (Neaverson). Microconch, C.73421, 
x 0-6, 17 feet below Blackstone. 


PLATE 15 


PLATE 16 


Pectinatites (Virgatosphinctoides) laticostatus sp. nov. Holotype (macroconch), C.73416, 
X 0:65, 19 feet below Blackstone. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 PLATE 16 


PAAR 17 


Pectinatites (Virgatosphinctoides) pseudoscruposus (Spath). Macroconch, C.73418, 
x0-7, 4 feet below Blackstone. 


17 


PLATE 


Bull. By. Mus. nat. Hist. (Geol.) 15, t 


I 


GEOL. 15, 


PLATE 18 
Pectinatites (Virgatosphinctoides) grandis (Neaverson). Macroconch, C.73420, 
4 feet below Blackstone. 


x 0°45, 


18 


PaaS: 


Bull. By. Mus. nat. Hist. (Geol.) 15, 1 


8§ 


GEOL. 15, I. 


PLATE 19 


Pectinatites (Virgatosphinctoides) grandis acceleratus subsp. nov. Holotype (macro- 
conch), C.73422, X 0-45, 13 feet above Rope Lake Head Stone Band. 


PLATE 19 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 


PLATE 20 
Fic. 1. Pectinatites (Virgatosphinctoides) woodwardi (Neaverson). Macroconch, 


C.73423, XI, 15 feet below Blackstone. 
Fic. 2. Pectinatites (Virgatosphinctoides) woodwardi (Neaverson). Microconch, 
C.73424, XI, 15 feet below Blackstone. The postulated original extent of the horn indicated 


by broken line. 


Bull. By. Mus. nat. Hist. (Geol.) 15, 1 PLATE 20 


a 


mati 


PATE 251 


Fic. 1. Pectinatites (Virgatosphinctoides) wheatleyensis (Neaverson). Macroconch, 
C.73425, X1, 12 feet below Blackstone. 


Fic. 2. Pectinatites (Virgatosphinctoides) wheatleyensis (Neaverson). Microconch, 
C.73426, x1, 12 feet below Blackstone. 


Fic. 3. Pectinatites (Virgatosphinctoides) wheatleyensis (Neaverson). Microconch, 
C.73427, XI, 15 feet below Blackstone. 


PLATE 21 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 


PLATE 22 


Pectinatites (Virgatosphinctoides) reisiformis sp. nov. Holotype (macroconch), C.73435, 
<1, 13 feet above Rope Lake Head Stone Band. 


Bull, Br. Mus. nat. Hist. (Geol.) 15, 1 PEAT E 22 


PLATE 23 


Fic. 1. Pectinatites (Virgatosphinctoides) reisiformis densicostatus subsp. nov. 
Holotype (macroconch), C.73437, 0°85, 13 feet above Rope Lake Head Stone Band. 

Fic. 2. Pectinatites (Virgatosphinctoides) reisiformis densicostatus subsp. nov. 
Paratype (microconch), C.73438, 0-85, 13 feet above Rope Lake Head Stone Band. 

Fic. 3. Pectinatites (Virgatosphinctoides) reisiformis sp. nov. Paratype (microconch), 
C.73436, x 0-85, 13 feet above Rope Lake Head Stone Band. 


23 


[PML NADAS, 


Bull. By. Mus. nat. Hist. (Geol.) 15, 1 


PLATE 24 
Fic. 1. Pectinatites (Virgatosphinctoides) wheatleyensis minor subsp. nov. Holotype 
(macroconch), C.73429, x 0:85, 17 feet below Blackstone. 
Fic. 2. Pectinatites (Virgatosphinctoides) reisiformis densicostatus subsp. nov. 
Intersex, C.73439, x 0°85, 13 feet above Rope Lake Head Stone Band. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 PLATE 24 


PLATE 25 


Fic. 1. Pectinatites (Virgatosphinctoides) donovani sp. nov. Holotype (macroconch), 
C.73441, 0°85, 30 feet below Basalt Stone Band. 

Fic. 2. Pectinatites (Virgatosphinctoides) donovani sp. nov. Paratype (microconch), 
C.73442, x 0°85, 36 feet below Basalt Stone Band. 

Fic. 3. Pectinatites (Pectinatites) cornutifer (Buckman). Microconch, C.73451, x1, 
6 feet above Freshwater Steps Stone Band. 


PAVE 25 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 


PLATE 26 


Fic. 1. Pectinatites (Pectinatites) eastlecottensis (Salfeld). Microconch, C.73449, XI, 
10 feet above Middle White Stone Band. 

Fic. 2. Pectinatites (Pectinatites) cornutifer (Buckman). Microconch, C.73450, XI, 
6 feet below Freshwater Steps Stone Band. 

Fic. 3. Pectinatites (Virgatosphinctoides) abbreviatus sp. nov. Holotype (macroconch), 
C.73440, <1, 20 feet above Rope Lake Head Stone Band. 


20 


PVA 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 


‘ 
rs vd 
2 < 


meme < 


PLATE 27 
Fic.1. Pectinatites (Virgatosphinctoides) encombensis sp. nov. Holotype (microconch), 
C.73444, XI, 21 feet below White Stone Band. 
Fic. 2. Pectinatites (Virgatosphinctoides) wheatleyensis delicatulus (Neaverson). 
Macroconch, C.73428, x1, 4 feet below Blackstone. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 PLRADE 27 


GEOL. 15,1. 9 


PLATE 28 


Pectinatites (Virgatosphinctoides) encombensis sp. nov. Paratype (macroconch), 
C.73445, 0-75, 33 feet below White Stone Band. 


Bull. By. Mus. nat. Hist. (Geol.) 15, 1 


IPL JN AE 1B: 


28 


PLATE 29 


Pectinatites (Virgatosphinctoides) magnimasculus sp. nov. Holotype (microconch), 
C.73443, XI, 21 feet below White Stone Band. The postulated rib density of missing parts of 
the shell indicated by broken lines. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 PVATLE 29 


PLATE 30 
Fic. 1. Pectinatites (Pectinatites) inconsuetus sp. nov. Paratype (micrconch), C.73447, 
<1, 10 feet above Middle White Stone Band. 
Fic. 2. Pectinatites (Pectinatites) inconsuetus sp. nov. Holotype (macroconch), C.73446, 
x 0-9, 10 feet above Middle White Stone Band. 


PLATE 30 


Bull. By. Mus. nat. Hist. (Geol.) 15, 1 


PLATE 33x 


Pectinatites (Pectinatites) groenlandicus (Spath). Macroconch, C.73448, x0-5, 10 feet 
above Middle White Stone Band. 


PLATE 31 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 


PLATE 32 


Fic. 1. Pectinatites (Pectinatites) naso (Buckman). Macroconch, C.73452, x1, 10 feet 
above Freshwater Steps Stone Band. 

Fic. 2. Pectinatites (Pectinatites) naso (Buckman). Microconch, C.73453, 1, 10 feet 
above Rope Lake Head Stone Band. 


BIA, 32 


Bull, By. Mus. nat. Hist. (Geol.) 15, 1 


PLATE 33 


Pavlovia (Paravirgatites) ci. paravirgatus (Buckman). C.73454, X 1-1, 10 feet above Fresh- 
water Steps Stone Band. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 1 PLATE 33 


ASK Muss 
ew? 
25 MAY 1967 


sg ~ 
SS S 
Sean We 


PRINTED IN GREAT BRI 
BY ADLARD & SON LIMI 
BARTHOLOMEW PRESS, DORKI} 


ee BULLETIN OF 
TH : BRITISH MUSEUM (NATURAL HISTORY) 
GEOLOGY Vol. 15 No. 2 
a LONDON: 1967 


THE CORRELATION AND TRILOBITE FAUNA < 
OF THE BEDINAN FORMATION (ORDOVICIAN) 
IN SOUTH-EASTERN TURKEY 


BY 


WILLIAM THORNTON DEAN, D.Sc. 


Pp. 81-123 ; 10 Plates; 4 Text-figures 


BULLETIN OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 
GEOLOGY Voll 15 "No.2 
LONDON : 1967 


THE BULLETIN OF THE BRITISH MUSEUM 
(NATURAL HISTORY), instituted in 1949, 1S 
issued in five series corresponding to the Departments 
of the Museum, and an Historical series. 

Parts will appear at irregular intervals as they become 
veady. Volumes will contain about three or four 
hundred pages, and will not necessarily be completed 
within one calendar year. 


In 1965 @ separate supplementary series of longer 
papers was instituted, numbered serially for each 
Department. 

This paper is Vol. 15, No. 2 of the Geological 
(Palaeontological) series. The abbreviated titles of 
periodicals cited follow those of the World List of 
Scientific Periodicals. 


World List abbreviation: 
Bull. Br. Mus. nat. Hist. (Geol.). 


© Trustees of the British Museum (Natural History) 1967 


AIO SAID IDS; (Os 
THE BRITISH MUSEUM (NATURAL HISTORY) 


Issued 13 June, 1967 Price {2 


mie CORRELATION AND TRILOBIDE BAUNA 
OF THE BEDINAN FORMATION (ORDOVICIAN) 
IN,SOUTH-EASTERN TURKEY 
By W. T. DEAN 


MS accepted November, 30, 1966 


CONTENTS 
Page 
I. INTRODUCTION AND ACKNOWLEDGMENTS < ¢ 0 0 5 Sal 
II. THE SUCCESSION AT BEDINAN : : : : : : 5 SH 
III. THE SUCCESSION NEAR SOSINK . : : a iG) 
IV. AGE AND RELATIONSHIPS OF THE BEpuvan Eien é : : QI 
V. SYSTEMATIC DESCRIPTIONS . : ; : 3 5 ; 5 Of 
Ampyx nitidus sp. nov. : : : : C ¢ oS 
Marrolithoides orthogonius sp. nov. c j : : 0 6S 
Marrolithoides laticiyvrus sp. nov. . F : : 3 5 99 
Cryptolithus? inferus sp. nov. 5 : ¢ : : 5 TOP 
Cryptolithus? bedinanensis sp. nov. : : : . 104 
Dionide formosa (Barrande) anatolica subsp. nov. . : 2) LOO 
Dalmanitina proaeva proaeva (Emmrich) . é : : 5 LTP 
Kloucekia phillips (Barrande) euvoa subsp. nov. . : > Rng 
Cheirurid gen. et sp. indet.  . c : o il 
Neseuretus (Neseuretinus) turcicus subgen, et SS nov. : . 115 
Brongniartella levis sp. nov. . : 2 : . < 5 Ulu) 
Platycoryphe? sp. : : : : . “ . 5 LAO) 
Colpocoryphe Spies , : é ZO 
Selenopeltis inernus (Beyrich) CGS EES. subsp. nov. : 5 WAI 
Asaphid gen. et sp. indet. . : : : : : a Uzi 
VI. REFERENCES . ¢ c : 0 : : : ey Muze 
SYNOPSIS 


The strata of the Bedinan Formation are described from the type region between Derik and 
Mardin, south-eastern Turkey. The rocks, which rest unconformably upon the Sosink Forma- 
tion (Cambrian), are mostly mudstones and shales but the highest of these pass upwards, 
apparently without a break, into a group of sandstones. The Bedinan Formation represents 
only a part of the Caradoc Series and there is an abundant shelly fauna which includes the 
following trilobites: Ampyx nitidus sp. nov., Marrolithoides orthogonius sp. nov., M. laticirrus 
sp. nov., Cryptolithus? inferus sp. noy., C? bedinanensis sp. nov., Dionide formosa anatolica 
subsp. nov., Dalmanitina proaeva (Emmrich), Kloucekia phillipsii ewroa subsp. noy., Neseuretus 
(Neseuretinus) turcicus subgen. et sp. nov., Brongniartella levis sp. nov., Platycoryphe? sp., 
Colpocoryphe sp., Selenopeltis inermis angusticeps subsp. nov. The trilobites, together with the 
less common brachiopods, exhibit marked Bohemian/Tethyan affinities and a tentative correla- 
tion with the Cernin and Chlustina Beds of Czechoslovakia is suggested. The graptolite 
evidence, though fragmentary, probably indicates the multidens or clingani Zone and is broadly 
in keeping with that of the shelly faunas. 


GEOL. I5, 2. 10 


84 ORDOVICIAN TRILOBILE PAUNA OF S.E> TURKEY 
I. INTRODUCTION AND ACKNOWLEDGMENTS 


ALTHOUGH large outcrops of Lower Palaeozoic rocks occur in south-eastern Turkey, 
between the Tigris and Euphrates valleys, relatively little published information is 
available. The best-known exposures lie along an elongated belt, up to almost 
3 km. wide, running east-south-east from a point 2 km. south-east of Derik towards 
Mardin, about 20 km. north-west of the Syrian frontier (for place names see Text- 
fig. 1). Tolun & Ternek (1952) gave a short description and small-scale maps of the 
Cambrian outcrops near Derik, and the highest part of the Cambrian succession as 
shown by them is known now to be Ordovician in age. Later Tolun (1960 : 236) 
noted the occurrence of Silurian rocks (sensu Jato including Ordovician) in south- 
eastern Turkey and mentioned a succession of 900 m. of marly and sandy beds with 
brachiopods, graptolites and trilobites underlying Cretaceous limestones at Bedinan. 
He remarked also on the similarity of the Bedinan Ordovician rocks to others found 
in bore-holes in northern Syria. The most important work dealing with this region 
is that of Kellogg (1960) who mapped a large area west of Mardin and gave detailed 
sections through all the stratigraphical subdivisions present, including the Cambrian 
and Ordovician rocks. He gave no comprehensive faunal lists but described the 
Bedinan Formation as containing, especially, “ Cryptolithus’”’ and “ Sowerbyella- 
like brachiopods ”’, which were held to indicate a Middle Ordovician age. Unfor- 
tunately Kellogg’s report remains unpublished, but reference will be made to his 
work from time to time in this paper. A chart of the rock succession in south- 
eastern Turkey, from Pre-Cambrian to Quaternary, was compiled by Gernot Schmidt 


TURKEY 


Malatyae sige 


Mardin 


Blecinicinl 


Gaziantep 


MEDITER 
-RANEAN 


SEA 


Fic. 1. Sketch-map of south-eastern Turkey showing location of place-names mentioned 
in text. 


ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 85 


in 1964 and revised in 1965. Again, this is a publication that I have been unable 
to find generally available, though some of its conclusions are noted later. 

During the Spring of 1965 my wife and I carried out field-work in the region 
between Derik and Mardin. Both the Cambrian and Ordovician successions were 
examined ; the latter are now described and it is proposed to describe the Cambrian 
faunas at a later date. Our work was greatly facilitated by the kindness of 
numerous Turkish friends. The Director, Dr. Sadrettin Alpan, and other members 
of the Maden Tetkik ve Arama Enstitiisti (M.T.A.), Ankara, generously placed the 
facilities of their organization at our disposal and we are particularly indebted to 
Dr. and Mrs. Kiragli, as well as to Mr. Giinal Aygiin who helped us in the field. 
In the Derik region we received much help from Dr. Karak6yunlu and members of 
the M.T.A. base-camp at the Mazidag, whilst the work of Mr. Abdurrahman Tung as 
guide and collector was invaluable. While working on comparative material in 
Czechoslovakia we received kindly assistance from Dr. Radvan Horny and Dr. 
Ladislav Marek. The graptolites we collected were examined by Dr. Isles Strachan. 
Finally, Prof. H. B. Whittington read the manuscript and made suggestions for its 
improvement. All specimens described in the present work are in the collections of 
the Department of Palaeontology, British Museum (Natural History). 


Il. THE SUCCESSION AT BEDINAN 

The village of Bedinan (sometimes written as Badinan or Bahdinan) lies in a 
valley about 20 km. east-south-east of Derik. The Ordovician rocks there form an 
inlier about 6 km. long and up to 3 km. broad elongated in an east-west direction. 
The inlier is bounded to the north by a prominent scarp and plateau of unconformable 
Cretaceous limestones, with a gentle northerly dip, and to the south by a large 
east-west dislocation, the Mardin Fault, which delimits massive Tertiary limestones 
having a variable southerly dip and sometimes slightly overturned. For the most 
part the Ordovician rocks comprise mudstones and shales with some intercalations of 
calcareous siltstone; the latter sometimes exhibit cone-in-cone structure and are 
more resistant to erosion than the adjacent mudstones. Higher in the succession 
the beds become more arenaceous and pass upwards conformably into a series of 
current-bedded sandstones, the age of which is discussed later. 

The principal section of the Bedinan Formation occurs to the west of the village. 
The succession there is almost totally argillaceous, broken only by occasional, 
sometimes concretionary, bands of siltstone. The strata have a slightly variable 
dip of rather more or less than 40° to the north-north-east, and by means of a traverse 
in this direction it was possible to sample the rocks in ascending order. The location 
and horizons of the principal fossiliferous localities are shown in Text-figs. 2 and 3. 
The lowest beds presumably occurring here form a low-lying area immediately 
adjacent to hills of more resistant Tertiary limestones, and could not be examined 
owing to the cover of Alluvium. Consequently it was impossible to confirm the 
suggestion, made elsewhere in this paper, that these lowest strata may probably be 
correlated, at least in part, with the relatively restricted Ordovician succession of 
the Sosink district. However, the lowest beds sampled (at localities B.1 and B.2) 
yielded Neseuretus (Neseuretinus) turcicus sp. nov., Colpocoryphe sp., Ampyx 


86 ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 


eet" o 

° ze O50 
SOI OO bins 
OSS Oso Gee 


oe 


o°o 


2 AL 


Cri. 2° 


Po% eo 09 8° 


| 


l 


———— 


So 


Yy Vt. / 


Fic. 2. Sketch-map showing principal fossil localities in the Ordovician rocks (horizontal 


shading) near Bedinan. Diagonal shading denotes Tertiary strata, whilst the remaining 
areas are covered by Alluvium. 


nitidus sp. nov., Cryptolithus? and Selenopeltis inermis angusticeps ssp. nov. Three 
of these genera are known from near Sosink but were not recorded from the succeeding 
strata near Bedinan. Dalmanitina and Kloucekia did not prove suitable for attempts 
to subdivide the Bedinan Formation, and were found to persist, virtually unchanged, 
throughout. 

Perhaps the least fossiliferous group of strata encountered in the traverse were 
those in the middle part of the section, including localities B.5-B.9. Nevertheless, 


ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 87 


sufficient material was collected to show that the fauna differs in no way from that of 
the higher beds. The strata in this and lower parts of the succession were disturbed 
by the intrusion of a dyke alleged by Kellogg (1960) to be of Quaternary age. The 
adjacent shales are often broken and collecting there is difficult, but the degree of 
metamorphism is not high and at one point, near locality B.9, relatively undistorted 
fossils were obtained within a few centimetres of the contact. 


ALLUVIUM 
B21 
B19 B20 
B18 
B17 
B16 
B15 
B14 
B13 
B11 & 12 
10 
Z B 
O 
= B9 
< 
= 
fad 
O B8 
Ses B7 
Bé 
B5 
0 SS 
<x 
FL, 
—_ B4 
(a) B3 
wi 
fea) B2 
———— Bl 
ite) 
Sv 
o 
rf 
£ 
1 
all 
—Mardin Fault 
Y 
TERTIARY 


Fic. 3. Diagrammatic vertical section of the strata just west of Bedinan, showing horizons 
of principal Ordovician fossil localities, Shading as in Text-fig. 2, 


88 ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 


The highest group of strata exposed in this section crop out along a hill-slope 
capped by superficial deposits. The beds mostly comprise grey-green shales which 
weather yellowish-brown and crumble easily. They are sometimes highly fossili- 
ferous, containing especially trinucleid trilobites (Cvyptolithus?), Dalmamitina and 
Kloucekia ; the specimens are often compressed, but occasional micaceous siltstone 
bands may yield less distorted material. Brachiopods, including the genera 
Aegivomena and Svobodaina, of Bohemian affinities, were found at several localities 
but proved particularly abundant at B.18—B.2r1. 

According to Kellogg, still higher strata near Bedinan may be examined in the 
area to the south-east of the village, and a traverse was made in that direction. 
His measured section shows the shale succession passing upwards into a thick series 
of sandstones, the age of which he put at “ Middle? or Upper? Ordovician ’’, these 
being followed in turn by unfossiliferous sandstones and shales of the Dadas Forma- 
tion, of “‘ Lower? Silurian”’ age. More recently Schmidt (1965) has assigned the 
Bedinan Formation to both the Ordovician and the Silurian, followed (though the 
nature of the contact is questionable) by the Dadas Formation, of alleged Devonian 
age. Whatever the relative merits of these two schemes, and there is as yet no 
definite faunal evidence to support either, it seems clear that the shales and mud- 
stones forming the bulk of the Bedinan Formation pass upwards conformably into a 
series of massive and flaggy, often current-bedded sandstones. The higher, more 
massive, arenaceous strata yielded no more than occasional indeterminate fragments 
of inarticulate brachiopods, but in the lower sandstones I was able to find occasional 
specimens of Dalmanitina and Kloucekia, apparently identical with the forms 
occurring so abundantly in the argillaceous strata near Bedinan. As discussed 
elsewhere in this paper, the faunas of the argillaceous Bedinan Formation suggest 
an horizon in the upper half, though not the highest part, of the Caradoc Series. 
Consequently there is no necessity to regard at least the lower portion of the 
succeeding sandstone sequence as being any later than Caradoc in age. 


FAUNAL List (for localities see Text-fig. 2) 


Ampyx nitidus sp. nov. B.2. 

Brongmartella levis sp. nov. B.18. 

Brongmartella sp. B.13, 19, 20. 

Cheirurid gen. et sp. indet. B.12. 

Colpocoryphe sp. B.1, 2. 

Dalmamitina proaeva proaeva (Emmrich) B.1-3, 6, 7, 10, II, 13-15, 17-22. 
Kloucekia phillips (Barrande) euroa subsp. nov. B.2-4, 6-8, 11-21. 
Cryptolithus? inferus sp. nov. B.r. 

Cryptolithus? cf. inferus sp. nov. B.2, 3. 

Cryptolithus? bedinanensis sp. nov. B.6, 8-16, 20, 22. 

Marrolithoides laticivrus sp. nov. B.3, 4. 

Marrolithoides sp. B.18? B.at. 

Neseuretus (Neseuretinus) turcicus subgen. et sp. nov. B.2. 
Platycoryphe ? sp. B.20. 


ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 89 


Selenopeltis inermis (Beyrich) angusticeps subsp. nov. B.1. 
Ostracoda indet. B.8, 17, 22. 

Aegiromena sp. B.1-3, 6, 8, 9. 

Lingula sp. B.7. 

Schizocrama sp. B.t. 

Svobodaina sp. B.2, 6, 8, 10-12, 17-21. 

Trematis? sp. B.13. 

Ribeiria sp. B.3. 

Miscellaneous, poorly-preserved bivalves B. 1-3, 6-8, 16. 
Sinuites (s.1.) sp. B.3. 

Hyolithids indet. B. 10. 

Lepidocoleus sp. 

Plumulites sp. B.10, 12, 13, 16, 22. 

Crinoid fragments, B.13, 20. 

Climacograptus sp. B.13. 

Diplograptus sp. B.8. 


III. THE SUCCESSION NEAR SOSINK 


Although the Bedinan Formation forms an elongated E-W outcrop some 5 km. 
by 1 km. just east of the village of Sosink, the strata are not well exposed. Much 
of the ground is covered by superficial deposits derived from the adjacent high 
ground to the east where Cretaceous limestones, dipping south, form a plateau-like 
unconformable layer, and the best exposures are limited to a section running 
N.N.W.-S.S.E. along the dip, in the vicinity of the small stone building known as 
Ziyaret (Text-fig. 4). The rocks, like those of the Bedinan district, consist essentially 
of grey-green mudstones and shales with occasional, harder bands of siltstone. The 
beds dip just east of south at an average angle of about 38° though with shght varia- 
tions, and the estimated thickness, calculated on the basis of a section through 
Ziyaret, is of the order of 440m. In general the rocks are poorly fossiliferous, 
though specimens may be locally abundant, occurring in thin bands. The mud- 
stones and shales are deeply weathered and crumble easily whilst the fossils are 
almost invariably preserved as orange, limonitic, internal and external moulds. 

The northern boundary of the Ordovician outcrop here is a fault, separating the 
beds from Cambrian sandstones which form a conspicuous feature immediately to 
the north. The fault has an indeterminate, small downthrow to the south and is 
thought to mask the unconformable base of the Bedinan Formation. The lowest 
Ordovician beds exposed are not far from the fault-line and proved only sparingly 
fossiliferous, locality A.1 yielding a single specimen of Colpocoryphe and a few 
poorly-preserved brachiopods. Much of the Ordovician succession exposed in the 
hill-slopes to the south-east of Ziyaret proved almost barren, and only a small 
number of specimens was obtained from locality A.2 though these did include 
Lasiograptus sp. and the holotype cranidium of Selenopeltis inermis angusticeps 
subsp. nov. in addition to the more commonplace fauna of Dalmamitina, Aegivomena 
and bellerophontid gastropods (Sinmites s.1.). 


90 ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 


The most prolific faunas of this area were collected from a number of localities in a 
small N.E.-S.W. valley excavated in shales some 180 m. north-west of the estimated 
position of the Cretaceous/Ordovician unconformity. In general the fossils were 
found in restricted horizons, no more than a few cm. thick, which could not be 
traced with certainty for more than a few metres. Trinucleid trilobites (Marro- 
lithoides) formed easily the most abundant constituent of the fauna, though 
Dalmanitina and Kloucekia were not uncommon. The presence of Dionide formosa 


ES 
= peteceeer esas ae ferves: 
i 7 L 

FS i —— ; lo L I 
a r : <7 St oe mh seceeeee ie oe 
Onn see See e sloseugen = ! 
Sgn Oppo eos Sa EEL Yee ee ot eenety See heel 
pee So eS NEES Tg (CRETACEOUS 
ns oor aeaoeureearnes SE a 
sRRUN LUM See es rhe ise el ee ee 


o-» 
© 


Fic. 4. Principal fossil localities in the Ordovician rocks near Sosink, 8 kilometres south- 
south-east of Derik. Shading as in Text-fig. 2, with addition of outcrops of Cambrian 
(dotted) and Cretaceous (brick pattern) rocks. Geological boundaries after Kellogg 1960. 


anatolica at three localities was of particular interest ; the species was found within a 
thickness of only a few metres of shales, and the genus is not yet known elsewhere in 
south-eastern Turkey. Brachiopods were relatively uncommon in the sections near 
Ziyaret, and comprised only Aegivomena, no doubt the “ Sowerbyella-like brachio- 
pods” of Kellogg’s account. Very few representatives of the more abundant 
brachiopod faunas (including Svobodaina) of the Bedinan district were found, 
probably owing to the stratigraphically lower level of the Ziyaret strata. The 
highest Ordovician strata in this area could not be examined owing to the cover 
of Recent superficial deposits, which also obscures the junction of the Ordovician 
and Cretaceous rocks. 


ORDIOVICTAN DRIP OBIT EE EH AUNAIOR Ss o2 . Df URE Ys gI 


Faunat List (for localities see Text-fig. 4) 


Asaphid gen. et sp. indet. A.6. 

Colpocoryphe sp. A.3. 

Dalmanitina proaeva proaeva (Emmrich) A. 1-6. 

Dionide formosa (Barrande) anatolica subsp. nov. A.3, 5, 7. 
Marrolithoides orthogonius sp. nov. A.3-6. 

?Neseuretus (Neseuretinus) turcicus subgen. et sp. nov. A.3. 
Selenopeltis inermis (Beyrich) angusticeps subsp. nov. A.2, 3. 
Aegivomena sp. A.2, 3, 4, 5, 7. 

Svobodaina sp. A.3. 

Sinumtes (s.l.) sp. A.2, 6. 

Redoma sp. A.3. 

Ribeinia sp. A.3. 

Bivalve indet. A. 3. 

Miscellaneous Ostracoda A.3, 6. 

Hyolithids indet. A.3. 

Plumulites sp. A.3, 4, 5, 6, 7. 

Climacograptus sp. A.3. 

Lasiograptus sp. A.2. 

Orthocone cephalopod indet. A.3. 


IV. AGE AND RELATIONSHIPS OF THE BEDINAN FAUNAS 


Perhaps the most obvious feature of the Beninan shelly faunas is their overall 
resemblance to those of the Bohemian region, even though the relevant Turkish 
forms are, for the most part, at least subspecifically distinct. The Bohemian trilobite 
species identical with, or most closely related to, those of the Bedinan Formation 
are as follows: Dalmanitina proaeva proaeva (Emmrich), Kloucekia phillips 
(Barrande), Dionide formosa (Barrande) and Selenopeltis inermis inermis (Beyrich) 
[= S. bucht (Barrande)]. From accounts of the Bohemian faunas published by 
Havli’ eck et al. (1958) and Snajdr (1956) the ranges of these species are as follows : 
D. proaeva proaeva, Cernin & Chlustina Beds; Dionide formosa, Cernin Beds. The 
lists of Havlicek e¢ al. show that Kloucekia phillipsti occurs only in the Chlustina 
Beds, its type horizon, but Snajdr records it from the Drabov Beds (basal Caradoc 
Series) to the Chlustina Beds. Selenopeltis inermis has an extended vertical range 
and is alleged to occur as low as the Dobrotiva Beds (Llandeilo Series) and as high 
as the Bohdalec Beds (topmost Caradoc). The species has been recorded (as 
S. bucht) by Seilacher (1963) from the Sinat Shales, of unspecified Ordovician age, 
in northern Iraq, not far to the east of the Bedinan district. 

In the Bedinan Formation Dalmamitina proaeva proaeva and Kloucekia phillips 
euvoa occur throughout most of the fossiliferous sequence, an association suggesting 
that a tentative correlation with the combined Cernin Beds and Chlustina Beds is 
not unreasonable. Dzonide formosa anatolica has been found only in the Sosink 
district, in the lower part of the Bedinan Formation, and this geological horizon may 
not be far removed from that of D. formosa in the Cernin Beds. 


92 OAR IDO) WAC ALAAING APIVICIL, O)ISI ADIT, VAN OP IY AN (OVID Sj 1B, I OP ARS WC 1) NZ 


The evidence of the remaining trilobites is inconclusive, though the species present 
may be potentially useful for correlation when other Tethyan faunas are better 
documented. Marrolithoides is a Llandeilo/Caradoc genus in north-western France 
and the Anglo-Welsh area, where Cryptolithus is found in the Llanvirn and 
Llandeilo Series, whilst Colpocoryphe is a fairly common constituent of Mediterranean 
faunas ranging in age from Arenig to Caradoc Series. Brongniartella is, above all, a 
genus of the Caradoc Series in the Anglo-Welsh area, most of its other occurrences in 
Europe and Scandinavia being as a single, widespread species, B. platynota (Dalman), 
in the Ashgill Series. Its appearance in the Turkish Caradoc is rather unexpected 
but suggests an easterly migration along the Tethys during Caradoc times, though its 
subsequent migration and development are far from clear. The new subgenus 
Neseuretus (Neseuretinus) is of particular interest as it may provide a link between 
European and Asian faunas of generally similar age. The horizon of N. (Neseuretinus) 
birmanicus (Reed) in Burma and China is obscure in terms of modern stratigraphy, 
but it forms part of Whittington’s (1966 : 723) Caradoc Encrinurella fauna. As 
pointed out elsewhere (Dean 1967) the age of the Encrinurella fauna may vary 
within the Caradoc Series, and is apparently greatest in Australasia. 

The number of graptolites found during the present field-work was disappointingly 
small and the specimens are poorly preserved, but Dr. Strachan has kindly examined 
them and supplied notes on their horizon. They include Diplograptus (s.s.) sp. 
and Climacograptus sp. near Sosink. Although little precise information can be 
given regarding their zonal position, Dr. Strachan considers all the specimens to be 
of Caradoc age. “‘ They are not pre-gvacilis [Zone], could well be multidens-clingant 
[Zone], and are unlikely to be linearis [Zone] or later ’’ (personal communication). 
Such an assessment accords well with the evidence of the trilobites, and supports a 
broad correlation with the Cernin and Chlustina Beds, sub-divisions which, in 
Bohemia, are overlain by the Bohdalec Beds, regarded as the topmost part of the 
Caradoc Series (Boucek 1937 : 454). 

All the other animal groups represented in the Bedinan Formation are in a minority 
by comparison with the trilobites. Brachiopods may be locally abundant, partic- 
ularly in the higher strata west of Bedinan, but are often poorly-preserved. They 
include, inter al., the genera Aegivomena and Svobodaina (Havlitek 1950 : 38, 100), 
indicating once more a close relationship with the Caradoc Series of Bohemia. The 
remainder of the fauna consists mainly of molluscs, represented by the almost 
ubiquitous Redonia and nuculids, together with gastropods, usually smooth forms of 
bellerophontid type generally resembling Simumites. The alleged phyllopod genus 
Ribewvia was found uncommonly near both Bedinan and Sosink. Hyolithids occur 
in small numbers but are usually incomplete and poorly-preserved, whilst plates of 
the machaeridian genera Lepidocoleus and Plumulites are not uncommon. All these 
groups form an assemblage broadly similar to many others in the Tethyan region, 
extending as far west as Portugal, Normandy, Wales and, probably, Florida. Such 
assemblages range in age from Arenig to Caradoc Series and many of the constituents, 
apart from the more obvious, diagnostic forms, exhibit relatively little morphological 
change, although a modern revision of the molluscs is still awaited. 


ORDOVICIAN TRILOBITE FAUNA OFS.E. TURKEY 93 
V. SYSTEMATIC DESCRIPTIONS 
Family RAPHIOPHORIDAE Angelin, 1854 
Genus AMPYX Dalman, 1828 


Ampyx nitidus sp. nov. 
(Pl. 5, figs. 5, 8-11) 


Diacnosis. Ampyx with broad, pear-shaped glabella, its greatest breadth 
measured one-third of distance from base of frontal spine to occipital furrow. Only 
traces of glabellar lobes. Triangular fixigenae relatively short, about one and a 
half times as broad as long. Pair of large pits near outer ends of posterior 
border furrow. Pygidium short, with median length about one-third frontal 
breadth. Axis poorly defined with at least two small axial rings. Side lobes have 
one pair deep, straight, pleural furrows. 


Horotype. It.118r (Pl. 5, fig. 8). 


EeranvPes: It .1180 (Ply 5, fig. 10): It.1207 (PI. 5; fig: 5)> It:1208 (Pl. 5, 
Hee); 1t.1200 (PI. 5, fig. rr). 

LOCALITY AND HORIZON. The species was found at only one locality, B.2, south- 
west of Bedinan, in the lower part of the Bedinan Formation there. It was 
accompanied by Cvyptolithus? inferus, Neseuretus (Neseuretinus) turcicus and 
inarticulate brachiopods (listed as Schizocrania sp.). 


Description. The cranidium, excluding the frontal spine which has not been 
found preserved, is subtriangular in plan with median length about half of the basal 
breadth. The glabella is subtrapezoidal in outline, bluntly pointed frontally, with 
the sides diverging forwards at about 50°. The maximum breadth is slightly more 
than three-quarters of the median length of the glabella (excluding frontal spine 
and occipital ring), and is measured across the intersection of the sides and the front 
of the fixigenae. About one-third of the glabella lies in front of the line of maximum 
breadth. Although there has been some dorsal compression, there can be no doubt 
that the original glabellar outline expanded forwards markedly. The glabella 
stands a little higher than the fixigenae and is separated from them by broad, shallow, 
slightly curved axial furrows which become deeper frontally and curve inwards, 
though the region of the anterior border is not preserved. The glabella carries only 
poorly-defined traces of lobation. A transverse, basal segment, representing the rp 
glabellar lobes, is delimited by a pair of shallow 1p glabellar furrows which run 
inwards and slightly forwards to join medially, where they become almost obsolete. 
Immediately in front of the basal glabellar segment are traces of a pair of semi- 
elliptical 2p glabellar lobes. The fixigenae are subtriangular and of moderate size, 
with about one-third of the length of the glabella projecting in front of them. The 
margins are straight and run backwards slightly for a short distance from the axial 
furrows as far as the facial sutures. Each of the latter meets the cephalic margin 
at an acute angle and from there pursues a gently flexuous course, at first slightly 
concave outwards and then slightly convex, before cutting the posterior border 
immediately outside a large, slot-like pit in the posterior border furrow. The 


94 ORDOVICIAN TRILOBIGE FAUNA OF SIE. TURKEY 


occipital ring is low, moderately broad (sag.), continuous with, but projecting 
backwards beyond, the transversely straight, ridgelike posterior border. The 
occipital furrow is mostly shallow but deepens a little abaxially where it joins the 
posterior border furrow. The latter is broad (exsag.) and shallow with a pair of 
pits sited near the outer ends [see above]. 

A single incomplete hypostoma was found (PI. 5, fig. 10), so small as to probably 
represent an immature individual. The median body is moderately and almost 
uniformly convex, bounded posteriorly and posterolaterally by a narrow, slightly 
raised border. The posterior margin is almost transversely straight, as are the 
posterior portions of the lateral margins which converge slightly backwards and 
meet the posterior margin at rounded, obtuse angles. 

The thorax is not known. 

One example of the pygidium was found, apparently only slightly compressed. 
The outline is transversely subelliptical, about three times as broad as long, its 
frontal margin transversely straight except medially, where a small articulating 
half-ring projects forwards slightly. The axis is triangular in plan, with the sides 
coverging backwards at about 35°. It is not strongly defined, stands only a little 
higher than the side-lobes, and reaches the posterior margin; two axial rings are 
visible. The side-lobes carry one pair of deep, straight pleural furrows, extending 
almost to the margins and delimiting a pair of half-ribs which are declined antero- 
laterally to form a pair of small facets. The impression of a broad doublure is 
covered with fine terrace-lines which run subparallel to the margin. 


Discussion. Ampyx nitidus is one of the youngest species assigned to the genus 
and exhibits marked differences from early forms of Ampyx. The type species, A. 
nasutus Dalman (see Whittington 1950 : 554) has a narrower, less divergent glabellar 
outline, with a smaller proportion of the glabella projecting in front of the fixigenae, 
which are also relatively longer. The Swedish species, which is of Upper Arenig 
age, possesses a pair of pits at the outer ends of the posterior border furrow, as does 
A. nitidus. This feature is not seen, or is less well developed, in species such as 
Ampyx linleyensis Whittard (1955: 18), from the Lower Llanvirn of the Shelve 
Inlier, and the Shropshire form is also distinguished by its broader glabella with 
smaller frontal projection, as well as by the well differentiated glabellar and alar 
lobes. The pygidium of the Turkish species is relatively shorter than that of 
Ampyx nasutus or A. linleyensis, has a more rounded margin, and the axis is less 
well defined and segmented. The hypostoma of A. nasutus is not yet known but 
that of A. linleyensis has a pear-shaped outline, posterior wings and lateral notches 
not seen in the incomplete specimen attributed here to A. mtidus. 

Ampyx virgimensis Cooper (1953: 16), from the Lower Edinburg Formation 
(early Caradoc) of Virginia, has been redescribed in detail by Whittington (1959 : 465). 
Like Ampyx nitidus it has a relatively short, rounded pygidium but differs from the 
Turkish species in having a shorter frontal projection of the glabella, as well as 
more distinct glabellar furrows and a strong development of alar lobes. As far as 
can be judged the hypostoma of A. mitidus appears to be more like that of A. 
virgimensis than that of A. linleyensis. Ampyx camurus Raymond (Whittington 
1959, pl. 30, figs. 15, 18, 19), also from the Edinburg Formation, has a cranidium 


ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 95 


generally similar to that of A. mitidus but the glabella is slightly narrower and the 
fixigenae are relatively longer, whilst the pygidium has a more triangular outline. 

Ampyx nitidus bears a general resemblance to A. abnormalis Yi (1957 : 557, pl. 5, 
figs. 3a-e), also of Caradoc age, from the Yangtze-Gorge District of China, but the 
Turkish species may be distinguished by its slightly longer cephalon, with the front 
of the glabella extending a little farther in front of the fixigenae, and the slightly 
shorter, more rounded pygidium. 


Family TRINUCLEIDAE Hawle & Corda, 1847 
Subfamily CRYPTOLITHINAE Angelin, 1854 


Marrolithoides, nowadays accorded generic rank, was erected by Williams (1948 : 
78) as a subgenus to differentiate Marrolithus-like trilobites in which the lateral 
cephalic margins are approximately parallel, the arrangement of fringe-pits is 
relatively simple, and the cephalic fringe is uninflated anterolaterally, except in 
gerontic forms. Since then Whittard (1956: 49, 63) has redefined the genus and 
transferred William’s species M. anomalis, regarded by its author as atypical of 
Marrolithoides, to Marrolithus. According to Whittard the criteria for distinguishing 
Marrolithoides are now as follows : (a) the cephalic outline is subrectangular ; (b) the 
fringe is not distended anterolaterally and there is no abnormal increase in pit- 
diameter there; (c) auxiliary pits are generally present in E,; (d) E,, I, and, 
sometimes, I, are continuous frontally ; (e) II, pseudogirder is almost as strongly 
developed as the normal E,—I, girder. Specimens from the Bedinan Formation 
which possess these features, together with unmistakable anterolateral angulation 
of the cephalic outline, may therefore reasonably be assigned to Marrolithoides. 
Individuals of this type occur in the succession east of Sosink and also at locality 
B.3, in the lowest part of the succession exposed near Bedinan, but the numerous 
trinucleids collected suggest that such generic limits as those listed above may be 
somewhat arbitrary. The angular cephala of B.3 are associated with smaller 
individuals—apparently immature examples of the same species—in which the 
outline is rounded anterolaterally. Similarly-rounded cephala, but of relatively 
large size and therefore presumably adult forms, occur at locality B.1 as well as 
from B.5 to the top of the succession near Bedinan. Trinucleid cephala possessing 
such rounded outlines together with a single row of pits external to the girder would 
normally be termed Cryptolithus sensu stricto, and the name is used here, with some 
doubt, for most of the Turkish specimens described. The latter, in general, show a 
greater development of concentric rows of pits than is customary for such forms as 
the type species C. tesselatus Green, from the Caradoc of eastern North America, 
and it is likely that the affinities of the Turkish specimens lie, rather, with species 
in Bohemia as well as those described by Whittard (1958 : 72-77) from the Llanvirn 
and Llandeilo Series of the Shelve Inlier. The latter group of species was said by 
Whittard to be distinct from those in North America, but there is as yet no evidence 
that they merit generic separation. On the basis of the above criteria the 
trinucleids of the lowest Bedinan Formation are placed in Marrolithoides. The 


96 ORDOVICIAN TRILOBITE FAUNA OFS.E. TURKEY 


remainder are attributed questionably to Cvyptolithus and there is a small strati 
graphical overlap of the two genera in the lower strata exposed south-west of Bedinan. 
The terminology used in the following descriptions is that of Whittard (1955 : 27) 
and the pit counts refer to half the cephalic fringe. 


Genus MARROLITHOIDES Williams, 1948 
Marrolithoides orthogonius sp. nov. 
(Pl. 1, figs. 1-9) 


Diacnosis. Marrolithoides with subrectangular cephalic outline and_ three 
concentric rows of pits [E,, I,_,] developed frontally, except for small irregular 
group near sagittal line. E,, I, pits of similar size; I, pits slightly larger. I,_; 
present, but I, represented by only few small pits. Average pit-count: E, + e, 26, 
IL+i, 21, 1,+i, 21, 1,+1, 18, 1,-+i, 17, 1;-1; about 14 of x5 [for 
variation see description]. 

Hororver. “1t71200%(PIAy, fie, 6): 


PARATYPES. It.747 (Pl. 1, fig. 4); It-749 (Pl: 1, fig: 8) >t. 760 5 Vee oastel 
fig 7); It. 803 (Plz, fiex2) 2 1t/806 (PIS, tie: 5) Galt. oz (Pl, fer pemieme ns 
(Rika ties @)cailitsSro) (ln n, ttee.3): 

LOCALITIES AND HORIZONS. The holotype and most of the paratypes are from 
the Bedinan Formation at locality A.3 in the section near Ziyaret, some 1300 m. 
east of Sosink. This locality yielded the species in greatest abundance, some 60 
specimens, whilst more than 20 were obtained from the same section at locality A.6, 
whence came two of the paratypes. Localities A.4 and A.5 produced only a few 
specimens of M. orthogonius. 


Description. The cephalon is approximately subrectangular in outline, more 
than twice as broad as long (excluding spines), though the proportions are obviously 
affected by dorsal compression, so that the cephalic fringe now appears flattened, 
in contrast to its original, steep declination outwards. The frontal margin, gently 
convex forwards in plan, forms a broad curve and meets at an obtuse angle the 
lateral margins, which are almost straight and converge forwards gently. The 
degree of anterolateral angulation seems to be genuinely variable, ranging from a 
broad curve, particularly in smaller specimens, to a relatively sharp angle. In one 
case (Pl. 1, fig. 5) the angle is marked by a blunt projection developed from the 
margin at about R16. The glabella is about twice as long as broad, stands high above 
the cheek-lobes, and narrows backwards slightly to a shallow occipital furrow which 
deepens laterally into a pair of apodemal pits. The best-preserved specimens show 
a small, median tubercle which is slightly more conspicuous on the internal than on 
the external mould. The glabella extends forwards a little beyond the cheek-lobes, 
from which it is separated by deep, straight, axial furrows, so that the cephalic 
fringe narrows (sag.) frontally. Each axial furrow contains a prominent hypostomal 
pit sited just behind the pitted fringe. Some specimens show faint, lateral indenta- 
tions of the glabella, suggesting almost obsolete glabellar furrows, but in most the 


ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 97 


glabellar margins are entire. One of the smallest specimens (Meraspis, Degree 
unknown, Pl. 1, fig. 7) shows, in addition to traces of eye-ridges, a conspicuous 
development of alar lobes; the latter are less obvious on both an example of 
Meraspis, Degree 4 (Pl. 1, fig. 9) and slightly larger cephala (PI. 1, figs. 1, 2), and are 
absent from the presumed adults. A deep occipital furrow separates the glabella 
from the narrow (sag.) occipital ring, which is steeply inclined backwards, produced 
upwards and back to form a thorn-like occipital spine approximately half the length 
of the glabella. The posterior border is narrow (exsag.) and transversely almost 
straight as far as the fulcra, where it flexes backwards a little way, becoming flange- 
like and indented to form a pair of articulating sockets. Beyond the fulcra the 
posterior margins of the cephalic fringe are almost transversely straight, and the 
backward projections of the fringe (so-called posterior wings) which characterize 
certain of the Bedinan Formation trinucleids, and are sometimes very large, are here 
noticeably absent. The small Meraspis figured here (PI. 1, fig. 7) shows the genal 
angles set well forwards, in front of the line of the posterior border furrow. This 
feature is shared with other cryptolithinids, and the position of the genal angles 
moved progressively backwards during ontogeny. Only incomplete examples have 
been found showing the librigenal spines ; these are directed backwards and slightly 
outwards from the genal angles, and apparently resemble those found in other 
members of the Cryptolithinae. Many specimens exhibit a conspicuous reticulation 
of the cephalic test, but in others it is less well developed or even, occasionally, almost 
absent. It is not yet clear whether such variation is original or due to vagaries 
of preservation. When present the reticulation is confined to the cheek-lobes and 
the axial portion of the glabella (see Pl. 1, fig. 1). 

The cephalic fringe is narrow (sag.) in front of the glabella, becomes broader 
laterally, attaining its maximum opposite the antero-lateral portions of the cheek- 
lobes, and narrows a little laterally, finally broadening again near the posterior 
border, where it expands around the posterolateral extremities of the cheek-lobes. 
Three concentric rows of pits, E, and I,_,, are almost continuous frontally, except 
for a small, irregular area near the sagittal line which appears to be of specific 
importance. At this point small cephala (see Pl. 1, fig. 4) exhibit a group of three 
pits arranged in a triangle with apex directed backwards. The anterior two pits 
form part of E,, whilst the hindmost pit may probably be regarded as part of L,, 
though sometimes it occupies a position between I, and I,. In larger cephala (see 
Pl. 1, fig. 8) the group of three pits is replaced by one of four pits, three of them 
corresponding to, and arranged in-line with, E,, and the centre pit of the three 
arranged radially with the fourth pit so as to form a radial row, Ro, coincident with 
the sagittal line. Additional concentric rows of pits are developed as follows: 
I, from R3 or R4; 1,4, from R6 or R7 (occasionally R5) ; I; from Rg (less commonly 
from Rio or Rr1); I,, when present, is developed only as a few pits in the area 
denoted by R1z to R15, or thereabouts. The pits of E, and I, are of similar size 
and show almost no variation in size over the whole of their length. The pits of I, 
are slightly bigger, also uniform in size, and a low ridge is developed between E, 
and I,, particularly anterolaterally. Although all the material is somewhat 
compressed there is a suggestion that the corresponding portions of I, may have 


GEOL. I5, 2. II 


98 ORDOVICIAN DRE OBE EE AUN ATOR See Die KeE ay, 


been raised slightly above the adjacent rows, but there is no indication of distended 
pits such as are found in the analogous parts of Marrolithus. The pits internal to 
I, diminish slowly in size towards the cheek-lobes and are often set in shallow radial 
sulci; the latter may be exaggerated by crushing, which may also overemphasize 
the radial extension of such sulci to include, apparently, pits of I, and I,; The 
number of pits along the posterior border of the fringe is generally about eight, in 
addition to a single, larger, apodemal pit. Apart from the area of irregular pitting 
near the sagittal line described above, the arrangement of pits is remarkably orderly, 
with a strong radial arrangement persisting from R, to within a few pits of the genal 
angles. Auxiliary pits occur only uncommonly, though an occasional specimen 
may have an extra pit or so on one side of the cephalon and not on the other. An 
example is shown in PI. 1, fig. 6, with E, containing two intercalated pits, between 
R3 and R4, and between R8 and Rg; these occur only on the right side of the 
cephalon. The number of pits present in the fringe is as follows, the first number 
indicates the number of pits most commonly found, the second, in brackets, shows 
the range of variation: E, 26 (23-28), I, 21 (20-24, rarely 25), I, 21 (20-22, rarely 
23), I, 18 (17-19, one specimen with 21), 1, 17 (15-18), I; approx. 14-15, but most 
material not suitably preserved ; I, either not developed, or present only as a few 
pits from a point varying from Riz to R15. 

The ventral side of the cephalic fringe carries an E,/I, girder which is well defined 
anteriorly, less so laterally, and finally becomes more pronounced again just before 
attaining the genal angle, where it forms a well-marked ridge which is continued along 
the librigenal spine. Between I, and I,, and between I, and I, are pseudogirders, 
each successively a little less strongly developed than the last but nevertheless well 
defined, and traces of additional pseudogirders occur between the remaining I rows. 

The thorax is known only from poorly-preserved material of characteristic 
cryptolithinid form, that is to say it contains six segments, the first of them macro- 
pleural. Each pleura ends in a blunt point, directed posterolaterally, and carries 
a broad (exsag.), straight, shallow, pleural furrow which runs gently backwards 
abaxially from the axial furrow almost to the pleural tip, near which it curves 
backwards slightly and dies out. 

The pygidium is subtriangular in plan with the transversely straight anterior 
margin broken only by the articulating half-ring. The lateral margins, defined bya 
small, raised ridge, are straight and widely divergent over the posterior two-thirds but 
then curve forwards to the anterolateral angles. The axis stands slightly higher than 
the flattened side-lobes and is gently rounded in cross-section. The anterior two-fifths 
of the axis carry three well-defined axial rings, gently curved and convex forwards 
in plan. The rings, which are not sharply delimited laterally, are separated by ring 
furrows which are continuous laterally with markedly shallower furrows traversing 
the side-lobes and running gently backwards to reach the marginal rim. The 
remainder of the axis has traces of several small, poorly-defined rings, and the tip 
merges into the marginal rim, here less sharply defined. The side-lobes carry only 
traces of furrows in addition to those continuous with the first three ring furrows. 
The pygidium of Meraspis, Degree 4 (Pl. 1, fig. 9) is semielliptical in plan and 
proportionately shorter than that of the adult trilobite. 


ORDOVICEAN LRILO BIDE EAN AY OW Sib. Tir ¥ 99 


Discussion. For convenience the species of Marrolithoides are discussed 
together (see p. 100). 


Marrolithoides laticirrus sp. nov. 


(BIZ) eGo ss Se. ater l 3) 


Diacnosis. Marrolithoides with cephalic outline broadly rounded frontally, 
angular anterolaterally. Large posterolateral extensions of fringe. Reticulation 
of glabella and cheek lobes characteristic in both small and, to lesser degree, larger 
individuals. Broad cephalic fringe contains four continuous concentric rows of pits 
(E,, I,-;) frontally ; remaining rows well developed. Pit count relatively high, 
average as follows: E, 36-38, I, 27-30, I, 26-30, I, 29, I, up to 26, I, 21, small 
development of I,. Pygidium with about nine axial rings and five pairs pleural 
ribs. 

HototyrPe. It.683 (PI. 2, fig. 5). 

Paw ubePp owt OQ0n (Pl 2 isan) Nt 7o0on( bl arte. 3) > lt.707 (Pl. 2, fig. 1) 
14.708 (Pl. 2, fic. 13); It.712 (Pl. 2, fig. 14) ; It.738 (PL. 2, fig. 0). 

LOCALITIES AND HORIZONS. The type material is from locality B.3, south-west 
of Bedinan, where it was found in moderate abundance (sample of 22 specimens) 
associated with Dalmanitina, Kloucekia and a single example of Cryptolithus? inferus. 
A few specimens from B.4, about 12 m. higher in the succession, differ from the type 
material in only small details and are considered to fall within the limits of variation 
for the species. 


DEscriPTION. The cephalon has a maximum breadth about two and a quarter 
times the median length. The lateral margins are straight or very slightly concave, 
and typically almost parallel, although some specimens exhibit a slight divergence 
or convergence which may have been exaggerated by crushing. The anterior 
margin of the cephalon is arched forwards, moderately in smaller cephala but more 
strongly in larger specimens. One of the latter, the holotype (PI. 2, fig. 5), shows the 
lateral and anterior margins meeting at obtuse but sharply defined angles which are 
in line with the highest point of the glabella, about one-third of the distance from 
the front of the glabella. The cephalic fringe is notably broad, with a frontal 
breadth (sag.) [measured on dorsally compressed specimens] equal to two-fifths of 
the glabellar length. Its maximum breadth is anterolaterally, behind which it 
narrows a little, just in front of the line of the posterior border furrow, before expand- 
ing again towards the genal angles, which are set well back, at the end of large genal 
prolongations. At the genal angles the lower lamella of the fringe is produced 
backwards to form a pair of prismatic librigenal spines, curving gently outwards at 
first and then inwards, with a length at least two and a half times that of the glabella. 
There is a strong, concentric arrangement of fringe-pits, usually with four continuous 
rows (E,, I,-;) developed in front of the glabella, but occasionally only three rows 
(E,, L-,). I, may be developed as far forwards as R3. The pits of I, are conspicu- 
ously the largest and maintain an almost uniform size to the genal angle. The 


100 ORD OWA CAN Tiksae OB iE SEAN UEN PAN OFS is) ase kKeB ays 


pits of I, are slightly smaller whilst those of E, and E, are slightly smaller still. 
The pits of subsequent I rows diminish steadily in size inwards from the girder. 
All the specimens are moderately compressed dorsally but most show a development 
of a sharp concentric ridge sited anterolaterally between E, and I,, and extending 
from about R6 to R2 or thereabouts. Some show a suggestion of a smaller I,, 
ridge anterolaterally. These structures suggest that the uncrushed cranidia may 
originally have had the anterolateral portions of I, raised slightly above neighbouring 
rows. The number of pits in each of the rows I,_, is fairly uniform but the number 
in E, is conspicuously higher and many of the pits there do not fit easily into a radial 
pattern. The region of the fringe internal to the girder exhibits a strong radial 
arrangement, comprising from seventeen to nineteen radii which cover an area 
extending to within a few pits (generally 3 or 4) of the posterior border. A sample of 
I5 specimens from the type locality yielded the following counts: E, + e, 36-38 
[in small cephala 29-34, rarely 26]; I, + i, 26-30 [occasionally 23-25]; I, +1, 
26-30 [occasionally 22-25]; I, +1, 26-29 [occasionally 23-25]; I,-+ i, is well 
developed in the holotype, with 27 pits from R3, but small cephala may have as few 
as 18 pits; I; + i; 10-19 [from R8 in a large cephalon, from R12 to R14 in a small 
one]; I, only a trace, perhaps a few pits from about R14—R16. At locality B.4a 
small sample of three cephala was obtained. These have a smaller pit count (33-34) 
for E, + e, than the type material but are otherwise similar and are attributed to 
the same species. The glabellar outline is clavate, expanded frontally where the 
maximum breadth is slightly less than two-thirds of the median length. Two 
pairs of lateral depressions represent the glabellar furrows, and the frontal glabellar 
lobe does not invade the cephalic fringe to any marked degree. The cheek-lobes are 
plump, quadrant-shaped, and their dorsal surface, like that of the axial portion of the 
glabella, is covered with a fine, mesh-like pattern of raised ridges. An occasional 
specimen shows a small, median tubercle at the apex of the glabella. The small 
occipital ring is produced backwards and upwards to form a small, sharp occipital 
spine. On the ventral surface of the fringe the girder is moderately developed, 
only slightly stronger than the pseudogirders I,/I, and I,/Is. 

The remainder of the exoskeleton is generally similar to that found in other 
members of the subfamily, with six thoracic segments of characteristic type. The 
subtriangular pygidium has slightly flexed, steeply declined margins surmounted 
by a thin, dorsal rim. There are about nine small axial rings separated by ring 
furrows, the anterior members of which cross the shallow axial furrows and are 
continuous with five or six shallow pleural furrows. 


Discussion. Marrolithoides orthogonius is the earliest-occurring trinucleid 
species yet known in the Bedinan Formation, and was found only in the upper part 
of the section east of Sosink. The not inconsiderable thickness of underlying shales 
there has yet to yield trinucleids, but the beds in question are inadequately exposed. 
M. orthogonius has not been found outside the Ziyaret district nor, conversely, have 
any of the trinucleid species from Bedinan been found elsewhere. This may be 
accounted for by the fact that the Ziyaret strata are probably older than the lowest 
seen west of Bedinan, and if any overlap of the sections occurs one would expect it 


ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 101 


to involve the strata under the alluvial cover adjacent to the Tertiary limestones 
cropping-out some 750 m. south-west of Bedinan. 

Judging from Williams’s drawings (1948, pl. 6, figs. 5, 7) the Welsh forms of 
Marrolithoides would appear to have very small fringe pits, but Whittard’s (1956, 
pl. 9, fig. 3) photograph of the holotype of MW. simplex, the type species, shows pitting 
of characteristic cryptolithinid dimensions, with the pits of I, slightly larger than the 
rest, a feature seen also in the Turkish material. The Anglo-Welsh species of 
Marrolithoides illustrated by Whittard (1956) possess cheek-lobes which are relatively 
much larger than those of the Turkish species ; consequently the cephalic fringes of 
the latter appear much broader although, in terms of concentric rows of pits, there 
is not much difference. M. orthogonius has a pit count not markedly different from 
that of M. arcuatus Whittard, of lowest Caradoc age at Shelve. However, the 
Turkish species tends to have more pits in E, and a larger development of I;, whilst 
a triangular group of 3 or 4 pits (z pit in I, and 2 or 3 pits in E,) forms a conspicuous 
feature at the sagittal line. Marrolithoides laticirrus differs markedly from all other 
species of the genus in its large, broad fringe with four, almost five concentric rows 
of pits in front of the glabella in the adult trilobite. Also notable is the large number 
of pits, including intercalated ones, in E,. The girder of M. orthogonius is more 
strongly developed than that of M. Jaticivrus, and in this respect the latter species 
has a ventral aspect more reminiscent of the species of Cryptolithus ? from the Bedinan 
Formation. 

The French species Tvinucleus bureau Oehlert (1895 : 300) was described from an 
unspecified Ordovician horizon in Brittany. Whittard (1956: 54) assigned T. 
bureau to Marrolithus but claimed it as a composite species and drew attention to 
the close resemblance of some of Oehlert’s illustrations to Marrolithoides simplex 
(Williams). The Breton species is in need of modern revision and, as described, may 
well include material attributable to both Marrolithus and Marrolithoides. Some of 
the specimens figured by Oehlert (e.g. 1895, pl. 1, figs. 1, 3) generally resemble M. 
orthogonius but the fringe is slightly broader anterolaterally, apparently the result of 
an extra concentric row of pits there, and lacks the characteristic median, triangular 
group of pits. The original of Oehlert’s pl. 1, fig. 15 compares with a paratype of 
M. orthogonius (see PI. I, fig. 5) but has one more pit row and greater differentiation 
in pit size than the Turkish form. 


Marrolithoides sp. 
(Pl. 4, fig. ro) 


In general, Marrolithoides occurs in the lower part of the Bedinan Formation, not 
only near Sosink but also south-west of Bedinan, where it overlaps stratigraphically 
with Cryptolithus ? inferus. The dominant trinucleid higher in the Bedinan Formation 
is Cryptolithus? bedinanensis but in some of the stratigraphically highest localities 
this is accompanied by uncommon forms which match best with Marrolithoides. 
The largest and most complete of these, It.881, is figured here from locality B.2r. 
It has a greater number of concentric pit rows than M. orthogonius, and although 
there are four frontal rows as in M, Jaticivrus it is separated from that species by 


102 ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 


having a straighter anterior margin and fewer, slightly larger pits in E,, whilst the 
pits of I, and I, are almost twinned near the sagittal line. I, is slightly raised, 
especially anterolaterally, and the pit-count is as follows: E, 29 or 29 estd; I, 22; 
I, 22: I,22; I, 20 (from R4) ; I; estd 17 or 18 from about R6 ; I, estd 16 from Rio. 
It is not evident whether I, is represented. Fragmentary evidence of Marrolithoides 
was also obtained from locality B.18. 


Genus CRYPTOLITAHUS Green, 1832 
Cryptolithus? inferus sp. nov. 
(Pl. 2, figs. 2, 4, 6-8, 12) 


DiaGnosis. Cryptolithus? with cephalon about twice as broad as long, its outline 
subangular anterolaterally and, occasionally, frontally. Cephalic fringe narrow 
(sag.) anteriorly with only three (E,, I,,), rarely two, concentric rows of pits 
continuous in front of glabella. I, generally developed from about R4. Several 
intercalated pits in E,, especially frontally and anterolaterally. Pit count relatively 
low, as follows: E, + e, 27-30; I, + i, 22-26; I, + 1, 21-22; I, + 1,19; I, + iy 
16-17 ; I, comprises about a dozen small pits in region of Rrio to R18; I, not 
developed. Reticulation of test weak or absent in large cephala. 


HOLORYPE melita 734m blezreticnss)s 
PARATYPE. It.735 (Pl. 2, fig. 6). 


OTHER MATERIAL. It.680) (Pl 2, fie. 12); Tt.607 (Pl, 2) tie. 7) = team (elie ae 
fica 4) elite 7045 Piezs tien 2)e 

LOCALITIES AND HORIZONS. The holotype and paratype are from locality B.1, 
south-west of Bedinan, where a sample of thirteen specimens was obtained from the 
lowest fossiliferous portion of the Bedinan Formation seen there. Another sample, 
also comprising thirteen specimens, from B.2, a little higher in the succession shows 
a pit count for E, + e, which is consistently higher than that for the B.1 material 
(31-34 pits compared with 27-30) and is here termed C. cf. inferus (see below). 
The specimens from the two localities are otherwise indistinguishable. A single 
cranidium of C.? cf. imferus (Pl. 2, fig. 12) was found at B.3, associated with 
Marrolithoides laticirrus. 


DeEscRIPTION. The cephalon is about twice as broad as long, sometimes slightly 
broader, especially in smaller specimens, and its outline is generally well rounded 
except frontally, where it may be almost subangular. The glabella is high, narrow 
and relatively long, occupying up to five-sixths or more of the cephalic length 
(excluding occipital spine). It expands forwards only slightly to the rounded 
frontal glabellar lobe, which extends a little in front of the cheek-lobes, and the sides 
are bounded by almost straight axial furrows. The latter contain a pair of elongated 
alar lobes in immature specimens, but these structures diminished during ontogeny 
and are absent from the presumed adult stages. Small specimens also exhibit 
reticulation of the test of the cheek-lobes and centre of the glabella, but in the largest 
examples from the type locality this is weak or absent. On the other hand several 


ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 103 


specimens from B.2 show stronger reticulation, but this may be no more than an 
accident of preservation 

The cephalic fringe is only moderately broad, especially frontally but also, to a 
lesser degree, anterolaterally and laterally. Frontally it is constricted slightly by 
the extension forwards of the glabella and contains three concentric rows of pits 
(E,, I,-,). E, extends to the genal angles and includes several intercalated pits, 
especially frontally but also anterolaterally and laterally. The pits of E, decrease 
slightly in diameter towards the genal angles, and frontally they are of approxi- 
mately similar size to those of I,. The pits of I, are larger than those of other 
rows and they, too, diminish a little anterolaterally. I, is developed from Kk3 or 
R4, I, from about Ro, and I; from about Rio to R1z. The following pit count 
is based on thirteen specimens from B.1: E,-+e, 27-30; I,+1, 22-26; 
I, +1, 22; I,+1, 19; I,-+ 1, 16. In the holotype I, consists of 12 small pits 
which extend from Rio to R17 or R18; the row then terminates until just in front 
of the posterior border furrow, where three further pits form an apparent continua- 
tion. The hindmost of these three is slightly the largest and probably represents the 
position of an apodeme, sited at the fulcrum and functional in the articulation of 
posterior border and first thoracic segment. The material available is insufficient 
to show whether this break in the line of I, is a reliable specific character, but a 
broadly similar break was found in at least two other specimens at the type locality. 
A sample of thirteen specimens from B.2, some 10 m. higher in the succession (see 
Text-fig. 3), gave the following pit count: E, + e, 31-34; I, +1, 22-23; I, +1, 
21-22; I, +i, 19 (from R2); I,+ 1, 17 (from R4). Again, I, is discontinuous, 
with twelve to thirteen pits anterolaterally and a further two or three near the 
posterior border furrow. The slightly higher number of pits in E, is not considered 
to justify separation of these specimens, which are listed and figured as Cryptolithus? 
cf. inferus (Pl. 2, figs. 2, 4, 7). The marginal cephalic suture is of normal trinucleid 
type and at the genal angles the lower fringe lamella is produced posterolaterally to 
form a pair of librigenal spines which are long and slender, at least twice the median 
length of the cephalon, prismatic in cross-section, and have a longitudinal ridge 
continuous with the E,/I, girder. In addition, two pseudogirders (I,/I, and I,/I,) 
are fairly well developed, particularly frontally. 

The thorax consists of six segments, the first of them slightly macropleural. The 
axis occupies about one-quarter of the total breadth, stands a little higher than the 
side-lobes, and is bounded by shallow, broad axial furrows. Each segment has a 
small, articulating half-ring separated from the axial ring by an articulating furrow 
which, on the internal mould, appears deep and broad (sag.) with a pair of apodemes 
sited abaxially. The pleurae are horizontal, parallel-sided, their tips obliquely 
truncated to form posterolateral points. Each pleura carries a broad, shallow, 
pleural furrow which runs almost straight from the anterior margin, at the axial 
furrow, and just fails to attain the pleural tip. 

The pygidium is closely similar to that found in other species of the genus, that is 
is to say its outline is an Isosceles triangle, three and a half times as broad as long, 
with a transversely straight frontal margin and broadly divergent, faintly sinuous, 
lateral margins. The small axis occupies one-sixth of the frontal breadth, tapers 


104 ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 


back to the tip, and is separated from the flat side-lobes by gently curved, shallow 
axial furrows. There are about ten axial rings, those after the sixth being less well 
defined. The side-lobes carry four and a half pairs of more or less well-defined 
pleural ribs, occasionally with traces of a fifth pair. 

A discussion of Cryptolithus? inferus and other species of the genus follows the 
description of C.? bedinanensis (see below). 


Cryptolithus ? bedinanensis sp. noy. 
(Pl. 3, figs. 1-7, 9; PI. 4, figs. 2-0) 

DiaGnosis. Cryptolithus with cephalon (excluding librigenal spines) about 
twice as broad as long, its outline rounded frontally, but with sides almost straight 
and slightly convergent forwards. Cephalic fringe moderately broad, typically with 
3 concentric rows of pits (Ej, I,_,) in front of glabella, and traces of ridge between E, 
and I, anterolaterally. I, well developed, and proportion of specimens with 4 rows 
of pits in front of glabella increases higher in stratigraphical succession. I,_, pits 
larger than those of adjacent rows. E, extends to genal angles and contains several 
intercalated pits. Pit count as follows: E, typically 32-36 but full range 26-38 ; 
I, 21-27, mostly 23-27 ; I, 21-26, mostly 23-25 ; I, 20-25, mostly 22-25 ; I, 16—23, 
mostly 18-21 ; I, 10-18, mostly 14-18 ; I, 6-13, mostly 7-10; I, rarely seen, with 
only very few pits. Thorax and pygidium of general cryptolithinid type ; latter 
has about ten axial rings and five and a half pairs of pleural ribs. 

Islowom7ns, Ie) (JPL 3. eS, 2, 3). 


lMUGaas, Iheospee (Hell, Swale, ) 3 Mc acasie (Vell, 3, saiey ©): 


LOCALITIES AND HORIZONS. The lowest stratigraphical occurrence of the forma 
typica is at B.6, south-west of Bedinan, where the largest sample (29 specimens) was 
obtained. This is also the type locality, and the greater part of the sample showed 3 
pit rows in front of the glabella, though a few had 4 rows (see PI. 3, fig. 1). The 
species was found subsequently throughout the remainder of the mudstone sequence 
of the Bedinan Formation and the proportion of specimens with 4 frontal rows of 
pits increased until the ratio of the two types at B.6 was almost reversed at B.16 
(for data, see below). 


DESCRIPTION. The entire dorsal exoskeleton of a slightly compressed individual 
is a little broader than long, approximately in the ratio 7:6. Just over half the 
median length is occupied by the cranidium, which is slightly more than twice as 
broad as long, the maximum breadth being measured across the genal angles. The 
outline is generally well rounded frontally and anterolaterally, but often straighter 
towards the genal angles. The glabella expands forwards gently in both height and 
breadth for about five-sixths of its length and then contracts to form a well-rounded 
frontal lobe. It is set higher than the convex cheek-lobes and is separated from them 
by broad, nearly straight, axial furrows. The latter become slightly broader 
posteriorly in the adult trilobite, and even more so in immature individuals so as to 
accomodate a pair of low, elongated alar lobes. As in other cryptolithinids the alar 
lobes became progressively smaller during ontogeny and eventually disappeared. 
The sides of the glabella carry two pairs of shallow impressions which represent 


ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 105 


glabellar furrows delimiting two small pairs of almost indiscernible glabellar lobes 
(Pl. 3, fig. 9). A shallow occipital furrow deepens abaxially to where, as seen on 
the internal mould, a pair of apodemes is sited behind the outer margins of the axial 
furrows. The occipital ring is short (sag.), slopes backwards gently, and is produced 
to form a slim occipital spine. The quadrant-shaped cheek-lobes extend forwards as 
far as the line of maximum breadth of the glabella. Both they and the axial portion 
of the glabella, which is surmounted by a small, median tubercle, frequently carry a 
fine, mesh-like ornamentation of raised ridges, though this is not always preserved 
and may not always have persisted in large individuals. In one or two immature 
examples a pair of fine nervures is visible on the cheek-lobes. The posterior border 
furrow is transversely straight, of only moderate depth, and becomes broader 
(exsag.) abaxially ; its posterior margin is more steeply inclined than the anterior. 
The posterior border is narrow (exsag.), ridge-like, transversely straight for less than 
half the distance from the axial furrows to the lateral margins ; it then meets a pair 
of fulcra and flexes down and slightly backwards around relatively small posterior 
prolongations of the cephalic fringe. In most trinucleids the cephalic fulcra are 
denoted by a pair of pits, often large, in the posterior border furrow. In the case of 
Cryptolithus? bedinanensis it is not clear whether they correspond to the hindmost 
pits of the innermost concentric row of the fringe. 

The cephalic fringe is of moderate breadth frontally, where 3 or 4 concentric rows 
of pits (E, and, respectively, L_, or L_-;) are developed in front of the glabella. 
The fringe becomes broader anterolaterally and laterally, where additional I rows 
soon appear. Many specimens show a low, thin ridge on the dorsal lamella, running 
between E, and I,, and diminishing frontally and posterolaterally. It is not clear 
whether this was a primary structure, but such a ridge could well have been formed 
by dorsal compression of a fringe in which I, was originally set slightly higher than 
the adjacent rows, particularly anterolaterally (see Pl. 4, fig. 6). In the case of 
cephala with 3 concentric pit rows at the sagittal line, the pitted area is invaded to a 
greater degree by the front of the glabella, and it was thought at first that there were 
grounds for separating such forms from others possessing 4 complete frontal rows 
and little extension forwards of the glabella. All now appear to fall within the 
limits of variation for the species but the proportion of specimens with 4 rows (even 
in small cephala) increases as one ascends the succession, as shown below. 


No. with 3 No. with 4 
Locality Sample frontal rows frontal rows 
B.6 29 18 2 OT 3 
B.8 6 I 2 
B.g I - I 
B.10 4 2 I 
B.11 2 = I 
B.12 6 4 2 
B.13 13 3 6 
B.14 3 I I 
B.15 II 2 5 
B.16 16 2) 12 
B.20 IT _ - 
B.22 4 > I 


106 OR DOW LCWAIN, dik ONS i sEVASWINFAM OIE S rus dl WORGK@ Hava 


When three frontal rows of pits are present the succeeding row, Is, is always well 
developed and may extend as far forwards as R3 or R4. Of the remaining rows, I, 
extends from R5 or R6 (occasionally R8 or Rg), I; from R7 to Rg (less commonly 
Rg to R15), whilst I,, although not always present in immature cephala, is usually 
found as far forwards as R12 to R15. I, is represented in only two specimens, from 
B.13 and B.16, by five small pits along the anterolateral boundary of each cheek- 
lobe. There is only one E row, extending to the genal angles and composed of 
numerous pits which greatly outnumber those of the I rows and are correspondingly 
more difficult to fit into a radial pattern. The I rows exhibit a strong radial arrange- 
ment which persists to within a few (generally 3 or 4) pits of the posterior border ; 
usually there are 17 to 21 radii, though occasionally up to 23 in individuals with a 
particularly high overall pit-count. The pits of I, and I, are of about equal size, 
somewhat larger than those of E, and I, which are also about equisized ; the pits of 
the remaining rows become smaller from I, to Ig. There are occasional deviations 
from this general rule and the pits of E, are sometimes slightly smaller than those of 
I,. The following table shows the variation in the number of pits present in 
individual concentric rows on the cephalic fringe of Cryptolithus? bedinanensis. A 
blank indicates that the material available was insufficiently well-preserved to 
obtain a reliable figure. At B.6 and B.13 the wide range of variation is accounted 
for by small cephala with a lower pit-count. 


No. in 
Locality sample E, +e, I, +i, I,+ i, I3 +ig Ig +i, I; +1, I, + ig Il 


B.6 29 26-36 23-27 21-26 21-25 16-19 10-14 Cc. 6-8 — 
esp. esp. esp. 
34-36 23-25 23-25 
B.8 6 27-31 21 22 22-23 18-19 — (Os 1K) — 
B.9 I 29 (G5 BP — — — — — — 
B.10 4 28-33 22-24 21-23 22 18 17 c. 10 — 
B.1t 2 33 23 C. 24 Oo Bit — —— a — 
18},162 6 290-35 25-26 24-26 22-25 13-18 c. 17 C.7 = 
18},703} 13 29-38 21-27 21-26 22-25 18-23 17-18 6-7 5 pits 
esp. esp. esp. in one 
33-38 23-27 24-26 specimen 
B.14 3 32-34 23-24 23-25 20 a 
B.15 bir 32-35 23-25 23-25 22-25 20-21 16-18 — — 
B.16 16 31-38 22-26 22-26 22-25 20-21 c. 16 5-6 5 pits 
in one 
specimen 
B.20 I — C. 24 — c. 20 = — oo = 
B.22 4 31 6.23 C. 23 23 20-21 c. 16 12-13 = 


On the ventral lamella of the cephalic fringe each genal angle is produced postero- 
laterally to form a long, slim, gently-curved librigenal spine. Each spine is prismatic 
in cross-section with longitudinal ridges, the lower of which extends a little way into 
the pitted area of the fringe and then bifurcates. Of the branches so formed, one is 
developed as a thin, sharp ridge, the true girder, between E, and I,; the other 


ORDOVICIAN TRIDOBITE PAUNA OF SE. TURKEY 107 


forms a slightly broader but lower ridge, the I,/I, pseudogirder. A further pseudo- 
girder is developed between I, and I, both frontally and anterolaterally, where it 
attains approximately the same dimensions as the I,/I, pseudogirder. These 
structures are shown clearly in Pl. 3, fig. 7. 

A few immature specimens of Cryptolithus? were collected from the Bedinan 
Formation and one of the smallest and best preserved is shown in PI. 3, fig. 8. It 
exhibits the features characteristic of a trinucleid Meraspis, including genal angles 
set in front of the line of the posterior border furrow, and well-developed alar lobes. 
The fringe is narrow, consisting almost solely of two concentric pit rows, but the 
count of 23 pits is high. 

The thorax consists of six segments, the first one macropleural, and is indistin- 
guishable from other members of the genus. Material from the type locality shows 
clearly that the pleural tips are blunt, almost vertical, and form a virtual continuation 
of the form of the anterolateral margins of the pygidium (see PI. 3, fig. 2). 

The pygidium is also of the form characteristic for the genus, with a low, narrow, 
marginal rim. The margin is moderately declined over the median third but 
becomes vertical anterolaterally (see above). In apparently adult examples the 
axis has the first four rings well defined, with only traces of a further six rings. 
Small specimens generally have better-defined axial rings which appear confluent 
with the pleural ribs (for example Pl. 3, fig. 6, probably Meraspis, Degree 5). The 
side-lobes carry about five and a half pairs of ribs, separated by broad (exsag.), 
shallow, pleural furrows which broaden towards the margin. 

A cranidium of unusual type (PI. 2, fig. 10) was found at locality B.6 in association 
with Cryptolithus? bedinanensis. It differs from the latter in having a particularly 
short glabella and lateral margins which, judging from the incomplete material, 
must have been slightly divergent forwards. The specimen is apparently malformed 
and therefore difficult to compare with other species. The concentric arrangement 
of pits is relatively irregular frontally, where I, is of normal type, I, is deflected 
slightly inwards, and E, is displaced markedly inwards from the margin. Conse- 
quently several pits, estimated as 6 or 7 on the complete cephalon, are arranged in 
interradial positions frontally, almost as an incipient E,. The specimen is listed 
merely as Cryptolithus? sp. 

Another example of a pathological cranidium was found at B.13 and is figured as 
Cryptolithus? cf. bedinanensis (Pl. 4, fig. 1). The left side generally resembles that 
species but on the right side E, does not extend as far forwards as the axial furrow, 
whilst I, and I, become irregular and flex forwards, the former row reaching the 
cranidial margin in front of the right axial furrow. 


Discussion. All the species of Cryptolithus described by Whittard (1958 : 72 
et seg.) from the Shelve Inlier were obtained from strata of the Llanvirn and 
Llandeilo Series and so are considerably older than the Turkish specimens. The 
Anglo-Welsh forms possess cheek lobes which are relatively large and extend 
forwards level with the front of the glabella, whereas in the Turkish material the 
glabella invariably extends beyond the cheek-lobes and often invades the pitted 
fringe area, to be accomodated by a flexing forwards of the inner concentric rows of 
pits. Another conspicuous point of difference is that the Anglo-Welsh specimens 


108 ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 


exhibit an unusually large range of pit size, those of the inner and posterolateral 
parts of the fringe being often exceedingly small; The Turkish specimens have the 
pits of I, and I, of approximately similar size, whilst the pits of all the other rows, 
although smaller, are never minute. An exception to these generalizations is 
offered by the cephalon of “ Cryptolithus sp.”’ figured by Whittard (1956, pl. 9, 
fig. 16) from the Lower Llanvirn of the Llandrindod area of Wales. In this form the 
pits are both fewer and of simpler disposition, features more reminiscent of the 
North American species of the genus, but only one example is yet known. Some 
of the specimens figured by Whittard have relatively large pygidia and in one 
individual (Whittard 1956, pl. 10, fig. 5) referred to Cryptohthus cf. inopinatus the 
pygidium seems atypical of that genus but strongly suggestive of Lloydolithus. It 
is, of course, possible that groups of trinucleids with rounded cephalic outline and 
one row of pits external to the girder arose independently from different genera, and 
may also have been differentiated geographically, but the evidence is not conclusive. 

A feature of all the specimens of Cvyptolithus? from the Bedinan Formation is the 
development of E, as a row of numerous small pits extending to the genal angle. 
This is reminiscent of the dorsal aspect of the cephalic fringe in Onnia Bancroft 
from the higher Caradoc Series of South Shropshire (for discussion see Dean 1960 : 
127), but in the latter case the pits of E, and I, are larger than, and raised above, 
those of adjacent rows, whilst radial sulci are well developed from I, inwards. The 
ventral fringe surface of Onnza is particularly distinctive, having a strong girder with 
two concentric rows of pits (E,_,) external toit. The girder itself is continuous with 
a ridge along the librigenal spine and there is a lesser development of pseudogirders 
between concentric rows internal to the girder, the I,/I, pseudogirder at least arising 
from a subsidiary branch of the main structure of ridge and girder. A somewhat 
similar condition is found in the Turkish specimens but with only a single E row 
developed. In addition some examples have the girder more weakly developed so 
that it appears scarcely more prominent than the adjacent pseudogirders. 

Cryptolithus? inferus shows only relatively small differences from the majority of 
the stratigraphically earlier members (including the types) of C.? bedinanensis, 
that is to say specimens which also have three concentric rows of pits in front of the 
glabella. C.? inferus typically has a much lower E, + e, count ; there is one fewer I 
row (this is particularly noticeable anterolaterally, where the fringe is narrower) ; 
and the anterior portion of E, consists of slightly larger pits with fewer intercalated 
pits. 

One can postulate an evolutionary sequence within the members of Cryptolithus? 
in the Bedinan Formation. The earliest representatives, typical C.? imferus, soon 
acquire a slightly higher number of pits in E, (the latter specimens are denoted as 
C.2 cf. inferus). Higher in the succession appears C.? bedinanensis which could have 
developed from C.? inferus by the addition of extra pits in almost all rows, and one 
concentric row internal to the girder. Further increase in the pits of I, led to the 
formation of four frontal rows in the majority of later members of the species, though 
the average count for individual rows does not apparently show any significant 
increase. 

Judging from the marked Bohemian affinities of the remainder of the fauna, one 


ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 109 


might expect to compare the Bedinan trinucleids with those of Bohemia, but the 
lack of relevant literature makes this difficult. Whittington (1940) considered the 
Czech species Tvinucleus ornatus Sternberg, 7. goldfusst Barrande and T. ultimus 
Barrande to be identical, and redescribed them as Onnia ornatus (Sternberg). The 
type material of all these species comes from different stratigraphical horizons and 
Marek (1952 : 23) has pointed out that Tvimucleus ultimus, at least, merits specific 
separation. Of the material illustrated by Whittington, his pl. 3, fig. 6 bears some 
resemblance to Cryptolithus? bedinanensis with three frontal pit rows (this paper, 
Pl. 3, fig. 3), but the pits of the outermost row seem fewer and rather more regularly 
arranged in the Czech specimen. The ventral fringe surface illustrated by Whitting- 
ton (1940, pl. 3, fig. 5) shows a girder and pseudogirders which are perhaps more like 
those of the Turkish specimens than in Onnza (s.s.). The original of Whittington’s 
pl. 3, fig. 6 was said to have been labelled as Tvinucleus goldfussi by Barrande, and 
the preservation in a fine-grained, buff sandstone (Whittington 1940 : 243) suggests a 
possible origin in the Letna Beds of the Caradoc Series. The specimen, a cranidium, 
has four frontal, concentric rows of pits, several rows anterolaterally, and the 
lateral margins are slightly divergent forwards. The outline is reminiscent of some 
examples of Marrolithoides laticiyrus, but the latter has a much larger number of 
pits in the outermost concentric row. Further discussion of these problems must 
await a modern revision of the Bohemian trinucleids. 


Family DIONIDIDAE Giirich, 1907 
Genus DIONIDE Barrande, 1847 
Dionide formosa (Barrande) anatolica subsp. nov. 
(Pl. 5, figs. 1-4, 6, 7, 12) 


DiaGnosis. Subspecies of Dionide formosa distinguished by following features : 
cephalic fringe longer (sag.) in front of glabella, with less well-developed marginal 
row of fringe-pits; genal angles turned backwards less strongly; pygidium 
proportionately shorter with slightly narrower axis, eleven to thirteen axial rings, 
and ten to twelve pairs pleural ribs. 


HOLoryer. It-ro6x (Pl. 5, figs. 1, 2). 


PAAnMeron Ui to570(Ple5, ne, 12). ltroo2 (Pl 5, tig. 6); It. 1063 (Pl. 5, 
emer tt 1178 (Bl 5, fie. 4); It-1201 (PI. 5, fig. 3). 

HoRIZONS AND LOCALITIES. All the type material is from the section near Ziyaret, 
east of Sosink, the holotype being collected from locality A.3 and the paratypes from 
A.3, A.5 and A.6. All these localities are believed to be in the lower part of the 
Bedinan Formation. 


DescriPTION. The cephalon, excluding librigenal spines, is transversely almost 
semielliptical in plan ; the median length varies from just over one-third to almost a 
half of the maximum breadth, according to the degree of crushing of the specimens. 
The tumid glabella is roughly subquadrate in outline, the frontal lobe rounded, 


110 ORDOVICIAN TRILOBILTE PAUNA OF SFE. TURKEMW 


convex forwards and bounded by a narrow (sag.), deep preglabellar furrow. The 
posterolateral portions of the glabella are formed by a pair of large lobes, almost 
reniform in plan, which project slightly beyond the lateral margins of the glabella 
and are set below the level of the median body. They are defined by a pair of broad, 
shallow furrows which deepen posteriorly. One specimen (PI. 5, fig. 4) shows the 
hindmost part of the glabella forming a depressed, neck-like structure, its anterior 
boundary immediately behind the posterior ends of the lateral lobes. As all the 
material is crushed, it is not clear whether this structure is primary. A narrow 
occipital furrow separates the glabella from a small, occipital ring which becomes 
shorter (exsag.) towards the axial furrows. Deep axial furrows separate the glabella 
from cheek-lobes which are almost quadrant-shaped, slightly broader than long. 
The cranidium is circumscribed by a narrow, low, marginal rim which is ridge-like 
frontally but becomes slightly broader and less inclined posterolaterally. Internal 
to the rim is a pitted fringe of the type characteristic for the genus, and this attains a 
breadth (sag.) frontally of between one-quarter and one-third of the length of the 
glabella ; this refers, of course, to compressed material and takes no account of any 
original inclination of the fringe. Laterally the line of demarcation between the 
fringe and cheek-lobes is difficult to distinguish, owing to crushing and the fact that 
both carry similar ornamentation. A comparable state of affairs was noted by 
Whittard (1958 : 99) when redescribing Dionide jubata Raymond. The cheek-lobes 
are separated by a broad (exsag.), posterior border furrow from a_ posterior 
border which is at first transversely straight and almost uniformly broad but then 
becomes narrower, turns back slightly, and finally coalesces with the hindmost, 
less inclined parts of the marginal rim described earlier. The surface of each cheek- 
lobe is traversed by a conspicuous, branched nervure which runs posterolaterally 
from the axial furrow, opposite the centre of the glabella, towards the genal angle. 
The nervure comprises thickened, irregular ridges whose development is somewhat 
variable. In two cases (PI. 5, figs. 4, 6) each nervure includes two branches which 
coalesce near the genal angle and then die out quickly. In another (PI. 5, fig. 3) 
only a single ridge is visible, whilst the holotype (PI. 5, figs. 1, 2) shows a third, 
smaller branch in front of the main pair, the anterior of which is slightly the thicker. 
The glabella is surmounted by a conspicuous median spine, rounded in cross-section 
and directed backwards and slightly upwards. In the somewhat crushed holotype 
the length of the spine approximates to that of the cranidium, but it was probably 
even longer originally. A similar structure in Dionide formosa was illustrated by 
Hawle & Corda (1847, pl. 3, fig. 16) but is not usually preserved. More recently, 
however, Curtis (1961 : 14) has noted a Portuguese example with the spine at least 
5mm. long. One specimen from the Bedinan Formation shows the left librigena 
(Pl. 5, fig. 3) which, although damaged, is seen to end in a long, curved librigenal 
spine, the original length of which is estimated to have been at least twice that of the 
cephalon. 

A complete thorax has not been found but one incomplete specimen (PI. 5, fig. 3) 
shows four segments, the first of them markedly macropleural. Another (Pl. 5, 
fig. 7), with pygidium attached, has five equisized segments and is also incomplete 
as it lacks a macropleural segment. It is reasonable to assume that six segments 


ORDOVICIAN DRIVOBITDE BAUNA OF Sle. TURKEY II 


would normally be present, the customary complement for the genus. The axis 
occupies just over one-fifth of the thoracic breadth, stands only a little higher than the 
side-lobes, and is bounded by narrow, almost straight, axial furrows which converge 
gently backwards. Each axial ring is almost rectangular in plan but ends antero- 
laterally in a well-defined pair of subtriangular axial lobes which are more 
conspicuous on the internal mould. The pleurae are transversely straight, parallel- 
sided, and terminate in blunt points directed posterolaterally. The breadth 
(exsag.) of the pleurae of the first, macropleural segment is about one-third that of the 
remaining segments. A pleural furrow runs from the anterior edge of each pleura 
immediately outside the axial furrow. At first it is deep and narrow, and runs 
almost to the centre of the pleura in a broad curve, concave forwards; it then 
becomes broader (exsag.) and shallower, and runs backwards very slightly, sub- 
parallel to the anterior margin, almost to the pleural tip, where it turns back more 
strongly and dies out. In the case of the macropleural first segment the pleural 
furrows are directed backwards more strongly, and the inner part of the anterior 
band (PI. 5, fig. 3) is inflated, as in Dionzde formosa formosa (see Whittington 1952, 
Text-fig. I). 

The best-preserved pygidium (Pl. 5, fig. 7) is shghtly more than three times as 
broad as long, sub-semielliptical in outline with the anterior margin almost trans- 
versely straight. Another specimen (PI. 5, fig. 12) appears to be proportionately 
longer but is more compressed. The axis, which occupies just over one-sixth of 
the frontal breadth, has the outline of an isosceles triangle, with well-defined straight 
sides converging backwards at about 20°. There are at least eleven axial rings on 
the first specimen, thirteen on the other, and the axis ends in a very small terminal 
piece just short of the posterior margin. The side-lobes have an almost flat surface 
which apparently becomes slightly declined near the pygidial margin, and they 
carry from ten to twelve pairs of pleural ribs in addition to the pair of anterior 
half-ribs. The well-defined pleural furrows become progressively more strongly 
directed backwards towards the rear of the pygidium. They are narrow and almost 
straight over most of their length (¢v.) but within a short distance of the margin 
they turn backwards and die out, apparently without attaining the margin, so that a 
narrow, smooth border results. In a few cases the furrows appear to intersect the 
margin, but this may be due to crushing. Faint interpleural furrows are visible on 
the adaxial portions of the first five or so ribs but become obsolete on the remaining 
ribs. 


Discussion. Many of the various species of Dionide have been enumerated and 
discussed during recent years by both Whittington (1952) and Whittard (1958). 
The Turkish specimens bear an overall resemblance to Dionide formosa (Barrande) 
and are probably of broadly similar age, but there are sufficient minor differences to 
warrant their separation as a new subspecies. First, the cranidium of D. formosa 
formosa has longer posterolateral genal prolongations, whilst the cephalic fringe 
contains a more conspicuous zone of marginal pits, larger and slightly more widely- 
spaced than those of D. formosa anatolica. Second, although the nervures of the 
two forms are of similar type those of the Turkish subspecies are apparently less 
strongly developed (judging from Whittington’s illustrations, 1952, pl. I, figs. I, 2, 


112 ORDOVICIAN TRILOBITE FAUNA ‘OF S7E) TURKEY 


5) whilst one specimen shows an additional branch. Third, the pygidium of D. 
formosa anatolica is better segmented, with a greater number of both axial rings and 
pleural furrows. The conspicuous nervures of D. formosa anatolica easily distinguish 
the new subspecies from forms such as D. jubata Raymond (of Llanvirn age) and 
D. euglypta (Angelin) var. quadvata Whittard (of Caradoc age ; see Whittard 1958 : 
g9-102). Duionide atra Salter may also be of Caradoc age but has an unusually and 
distinctively large number of axial rings and pleural ribs (Whittard 1959 : 98). 
Diomide turbulli Whittington (1952: 8), from the Llanvirn Series, differs from D. 
formosa anatolica in having a much broader cephalic fringe with radiating ridges, 
very long genal prolongations, and a pair of strongly-developed, single nervures. 
Dionide hybrida Reed (1915 : 26, pl. 5, fig. 7), from the Hwe Mawng Beds of Burma 
(exact age uncertain), has a cephalic outline similar to that of D. formosa anatolica 
but the glabella, which carries a median tubercle, is relatively larger, whilst the 
fringe is narrower and has coarser pitting, especially marginally where there is a 
conspicuous row of large pits. No nervures are visible in Reed’s illustrations or 
noted in his description, but the species is founded on only a single, abraded specimen. 
Dionide asiatica, from the Ordovician of Eastern Yunnan, was founded by Kobayashi 
(1940 : 205) on the specimen figured by Mansuy (1912 : 37, pl. 6, figs. 2a, b) as D. 
formosa. Though broadly similar to D. formosa formosa and D. formosa anatolica, 
Mansuy’s specimen may be distinguished by the following features: the nervures 
are less strongly developed ; the frontal part of the cephalic fringe is much narrower 
(sag.) ; there is a marginal row of conspicuously large fringe pits ; the pygidium is 
relatively longer and better segmented with twenty-five axial rings and about 
sixteen or seventeen pairs of pleural ribs in addition to the anterior pair of half-ribs. 


Family DALMANITIDAE Vogdes, 1890 
Genus DALMANITINA Reed, 1905 
Dalmanitina proaeva proaeva (Emmrich) 
(Pl. 6, figs. I-9, 11-13; Pl. 7, figs. 4, 5) 
1839 Phacops proaevus Emmrich : 25. 
1956 Dalmanitina proaeva proaeva (Emmrich) Snajdr: 513, pl. 4, figs. 10, 11; pl. 5, fig. 4. 

Includes discussion of species. 

The species and subspecies of Dalmanitina in the Caradoc and Ashgill Series of 
Bohemia have been revised by Snajdr (1956). They comprise, in ascending 
stratigraphical order: D. proaeva cilinensis Snajdr, Drabov Beds; D. proaeva 
socialis (Barrande), Letna Beds; D. proaeva proaeva (Emmrich) [Snajdr lists this 
only from the Chlustina Beds but Havlicek and others (1958) record it also from the 
underlying Cernin Beds] ; and D. proaeva grandis (Barrande), Kraltiv Dvur Beds. 

Three pygidia of D. proaeva proaeva from the Chlustina Beds, figured by Snajdr, 
exhibit a small amount of variation. One (Snajdr 1956, pl. 4, fig. 10) has ten axial 
rings and seven and a half pleural ribs ; another (pl. 4, fig. 11) shows nine axial rings 
and seven and a half pleural ribs ; whilst the third (pl. 5, fig. 4) has nine axial rings 
and eight and a half pleural ribs, as far as can be judged. There is a strong overall 


ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 113 


resemblance to the pygidium of D. proaeva socialis but the latter, while possessing a 
similar number of pleural ribs, has deep, relatively broad (exsag.) interpleural 
furrows, whereas those of D. proaeva proaeva, although distinct, are narrow and 
shallow. 

Remains of Dalmanitina were found, in varying concentrations, throughout most 
of the Bedinan Formation, but although a certain amount of variation was observed 
it has proved insufficient to demonstrate the presence of more than one form. The 
hindmost axial rings and pleural ribs of some pygidia are not well defined but in 
general the range of variation is limited. The number of axial rings ranges from 
eight to ten (rarely traces of an eleventh), and of pleural ribs, from seven and a half 
to eight and a half (very rarely six, in imperfect material), figures which accord 
well with those for D. proaeva proaeva. The specimens all exhibit the broad pleural 
furrows and narrow interpleural furrows of the Czech species, and there are 
insufficient grounds for separating the two. Many of the Bedinan pygidia end in a 
terminal spine of varying length, usually short on the internal mould, owing to 
partial infilling of the internal cavity, but sometimes considerably longer on the 
external mould. Most of the best-preserved specimens have the spine about as long 
as the remainder of the pygidium, but one is exceptional in being almost one-and-a- 
half times as long (PI. 7, fig. 5). The specimens are identical in all other respects. 

The cephala of both D. proaeva proaeva and D. proaeva socialis are virtually 
identical, and are closely matched by the Turkish specimens. Two hypostomas 
were collected (see Pl. 6, figs. 7, 9) and although slightly compressed (one more so 
than the other) they resemble that of D. proaeva socialis illustrated by Barrande 
(1852, pl. 26, fig. 21). 

LOCALITIES AND HORIZONS. Dalmamnitina proaeva proaeva was found in moderate 
numbers in the lower part of the Bedinan Formation as seen to the east of Sosink. 
The lowest record was from locality A.1, but the species proved more abundant higher 
in the succession and was found at A.2-6, especially A.3. In the Bedinan district, 
presumably higher in the succession, D. proaeva proaeva was collected from many 
of the localities examined but occurred in greatest abundance in the upper part of the 
exposed section, covered by localities B.17-21. 


Genus KLOUCEKIA Delo, 1935 
Kloucekia phillipsii (Barrande) euroa subsp. nov. 
(BING; fies r0)7 Plz, fies; 1-3,6; 7,,0,122) 

DiacGnosis. Subspecies of Kloucekia phillips: dintinguished principally by 
the pygidium, which has eight or nine axial rings and usually five or six pairs of 
pleural ribs, the latter separated from each other by deep pleural furrows carrying 
moderately-impressed interpleural furrows. 

HOLoryer. If. 1188s(Pl. 6; fig. 10; Pl. 7, figs..9, 12). 

EARARV EES = lenbio7s(bhe7, ties, 0, 7h. Lt 1189 (Pl. 7, fig. 3); It:1223: (Pl: 7, 
nies 2); Lt.1225 (Pl.7; fig: '2). 

LOCALITIES AND HORIZONS. K, phillipsii euroa is one of the most abundant and 
characteristic trilobites of the Bedinan Formation in the Bedinan district, where it 


GEOL, I5, 2. 12 


I14 ORDOVICIAN TRIEOBITE FAUNA OF SE. DURKEY 


was collected from all but the lowest strata. It was not found in the Bedinan 
Formation east of Sosink, probably because the beds there are stratigraphically lower 
than those near Bedinan. 


DEscRIPTION. The type species of Kloucekia, Phacops phillips Barrande (1846 : 
27; 1852: 557, pl. 22, figs. 1, 2, pl. 26, figs. 31-36), has recently been redescribed by 
Whittington (1962 : 7, text-fig. 2a-1) using specimens named originally by Barrande. 
Most of these came from Zahorzany, Bohemia, in strata once known as the 
Zahorzany Beds but which would nowadays be termed the Chlustina Beds, of fairly 
high Caradoc age. From a study of Whittington’s illustrations it is clear that there 
are many points of resemblance between the Czech and Turkish specimens, and it 
has not proved possible to make a satisfactory differentiation on the basis of the 
cephalon and thorax. In certain cephala from the Bedinan district the glabellar 
furrows appear to run backwards from the axial furrows a little more strongly than 
do those of K. phillips, but this could easily be accounted for by variation in 
preservation. Some of the Turkish specimens (see especially Pl. 7, fig. 2) have a 
V-shaped group of tubercles on the median portion of the frontal glabellar lobe ; 
such a feature, though not uncommon in numerous phacopid and dalmanitid genera, 
is not always preserved. One of Whittington’s photographs (1962, text-fig. 2h) 
shows that the cephalic doublure of K. phillipsi possesses a vincular furrow, and a 
similar structure is found in K. phillipsi euroa (see Pl. 7, fig. 7), though perhaps a 
little more strongly developed. 

The most obvious differences between the two forms are to be found in the 
pygidium. That of K. phillipsi has three well-defined axial rings, followed by two 
fainter rings and a small terminal piece, whilst the side-lobes have four pairs of deep 
pleural furrows, the ribs so-formed carrying faint interpleural furrows. The 
pygidial axis of K. phillipsu euroa has five, occasionally six, well-defined axial rings, 
followed by three less well-defined rings (the last two ring furrows do not cross the 
sagittal line), and ends in a very small terminal piece. The side-lobes of the Turkish 
subspecies usually carry five pairs of deep pleural furrows, though sometimes there 
are Six or, more rarely, seven pairs. Five well-developed pairs of interpleural fur- 
rows are present, which cross and indent the otherwise almost smooth, gently concave 
border, and there is usually a trace of a sixth pair. In general the pygidium appears 
to be proportionately broader than that of K. phillipsiz, but it would be unwise to 
assume that this is the case when the material is usually somewhat compressed. 
According to Snajdr (1956 : 39) the vertical range of K. phillipsii in Bohemia is 
from the Drabov Beds to the Chlustina Beds of the Caradoc Series, but the range of 
K. phillips euroa may be more restricted as it has not been found in the lowest part 
of the Bedinan Formation, nor has it yet been recorded outside Turkey. 


Family CHEIRURIDAE Salter, 1864 
Cheirurid gen. et. sp. ind. 
(Qed, suey atiee, 3) 


An incomplete thoracic segment, figured here as a latex cast, is the only representa- 
tive of the cheirurids so far found in the Bedinan Formation. The specimen shows 


OR DOVUCEAN GE RIMO BIg Ee AUN Ss OF (Ser TURKEY 115 


part of the axial ring, bearing a small axial lobe, delimited by an axial furrow which 
is shallow medially and deepens to both front and back. The pleura is parallel- 
sided for most of its length (¢.) and curves backwards, at first only gently and then 
more strongly, to end in a long, pointed tip, directed posterolaterally. The posterior 
margin has a small posterior flange, the outer part of which is not preserved, whilst 
an anterior flange of generally similar size expands conspicuously towards the 
fulcrum, where it ends in a projecting, articulating process. A shallow pleural 
furrow divides the pleura into two subequal bands, the anterior of which is slightly 
the narrower (exsag.). Along the pleural furrow is distributed a somewhat irregular 
row of almost equisized pits which begins just outside the axial furrow and ends 
without quite reaching the fulcrum. The material is insufficient for firm identifica- 
tion, but similar characters are to be seen in the thorax of Placoparina, a genus of 
Llanvirn—Llandeilo age (see Whittard 1958 : 112). 


LOCALITY AND HORIZON. B.12, to the west of Bedinan, in the upper part of the 
Bedinan Formation exposed in the section there. 


Family SYNHOMALONOTIDAE Kobayashi, 1963 
Genus NESEURETUS Hicks, 1876 
Subgenus NESEURETINUS nov. 


TypeE SPECIES. JN. (Neseuretinus) turcicus sp. nov. 

DiacGnosis. Subgenus of Neseuretus distinguished by large, inclined, anterior 
border, with convex, transversely straight, preglabellar field delimited by 
conspicuous preglabellar and anterior border furrows. 


DISTRIBUTION. South-eastern Turkey, Burma and southern China. 


Neseuretus (Neseuretinus) turcicus sp. nov. 
CPi. tigses, 10) Li; sel.) figs. 14) 


DiaGnosis. As for subgenus. 
Hototyre. It.1179 (Pl. 9, figs. 1-3). 
PARATYPE. It.1205 (Pl. 9, fig. 4). 


LOCALITY AND HORIZON. The species is known with certainty from only locality 
B.2 at the section south-west of Bedinan, where it occurs in the lower part of the 
Bedinan Formation. A pygidium tentatively referred to the new form (see PI. 
7, figs. 8, 10, II) was recovered from a probably similar horizon at locality A.3, 
east of Sosink. 


DeEscrRIPTION. The species is represented by two incomplete cranidia preserved 
as internal and external moulds. The cranidium is moderately convex both 
longitudinally and transversely, with median length estimated as being slightly 
more than half the maximum breadth. The glabella is fairly convex, especially 
transversely, trapezoidal in outline, narrowing forwards so that the frontal breadth 
is a little more than half the basal breadth. There are four pairs of unequal 


GEOL. 15) 2. 128 


116 ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 


glabellar lobes, diminishing in size from back to front of the glabella. The fourth 
lobes are the largest, their length about one-third that of the glabella, and subcir- 
cular in outline, becoming subangular anterolaterally. The fourth glabellar furrows 
are deeply incised, running straight inwards and slightly backwards from the axial 
furrows for more than half their length (¢.) but then turning more sharply backwards 
and terminating so as to leave a pair of “ necks ’’ connecting the basal lobes to the 
median body. There is no obvious bifurcation of the basal furrows but at their 
midpoints they become notably broader, with the adaxial margins steeply bevelled. 
The third glabellar lobes are transversely subrectangular in plan, their long axes 
strongly divergent forwards, and they are bounded by parallel, well-defined third 
glabellar furrows which are deepest adaxially. The second glabellar lobes are 
generally similar to, though smaller than, the third pair, but expand slightly at their 
outer ends, the second glabellar furrows becoming correspondingly less divergent 
forwards, The second, third and fourth pairs of furrows end adaxially in-line so as 
to leave a smooth median body which is almost parallel-sided and occupied just less 
than one-third of the basal glabellar breadth. Immediately in front of the second 
glabellar lobes the glabella narrows slightly, forming a small “ step ”’ in the outline. 
The first glabellar lobes are very small, about half the length (exsag.) of the first 
pair, and poorly defined frontally by first glabellar furrows which are little more than 
inconspicuous, shallow notches, The frontal glabellar lobe is very short, and the 
almost straight anterior margin has a shallow median indentation. The length 
(exsag.) of the frontal lobe diminishes markedly towards the posterolateral angles, 
which are less well defined than the remainder of the lobe and appear to extend 
abaxially just beyond the first glabellar lobes. The axial furrows are deep and 
broad, converging forwards in straight lines as far as the second glabellar furrows, 
beyond which they become more diffuse, meeting the well-defined preglabellar 
furrow and “ anterior furrows ”’ (see later) at a pair of broad depressions in which a 
pair of hypostomal pits is sited approximately opposite the mid-point of the frontal 
glabellar lobe. The distance from the front of the glabella to the anterior margin of 
the cranidium is estimated to be a little more than two-thirds of the glabellar length, 
that is to say it is unusually long for the genus, and is composed of two distinct parts, 
an anterior border and what appears to be a true preglabellar field. The anterior 
border is relatively large, longest (sag.) medially but shortening abaxially, strongly 
arched transversely, and fairly steeply inclined forwards to form a scoop-like front 
to the cranidium. The preglabellar field is well developed, its surface strongly 
convex, standing slightly higher than the front of the glabella. In plan it is trans- 
versely subrectangular, defined posteriorly by the almost straight preglabellar 
furrow and anteriorly by a deep, broad (sag.), anterior border furrow which is well- 
rounded in cross-section. The outer ends of the preglabellar field are truncated by 
broad (d.), moderately-deep furrows which form forwards extensions of the axial 
furrows. Whittard (1960:143) introduced the term “anterior furrows’”’ for 
apparently similar structures seen in other species of Neseuretus, defining what he 
described as the “ anterior area ’’, believed by him to represent the combined anterior 
border and preglabellar field. In the new species there can be little doubt that a 
true preglabellar field is present, so that the furrows truncating it laterally are 


ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 117 


equivalent to the posterior portion of Whittard’s anterior furrows. The palpebral 
lobes are sited opposite the second glabellar lobes and the third glabellar furrows. 
They are unfurrowed, strongly convex outwards in plan, stand a little lower than the 
adjacent parts of the glabella, and have their surface gently declined adaxially. 
The fixigenae are convex, arching downwards to both front and rear from the 
vicinity of the palpebral lobes. The gonatoparian facial suture is of the type 
characteristic for the genus. The surface of the test is incompletely known, but 
that of the anterior border is finely granulated, whilst the glabellar lobes, median 
body and preglabellar field carry coarser tubercles. 

The remainder of the exoskeleton is unknown with certainty but a single, 
incomplete pygidium of appropriate type from near Sosink is referred questionably 
to the new species (Pl. 7, figs. 8, 10, 11). The specimen has undergone slight 
compression but is not unduly distorted. The axis extends to, or almost to, the tip 
of the pygidium and its frontal breadth is just over one third of the total breadth, 
which is measured just in front of centre. In addition to the articulating half-ring 
there are seven well-defined axial rings, followed by two less distinct rings (as far 
as can be judged) and a small terminal piece. The ring furrows all deepen abaxially 
and there is a break in the outline of the axis behind the fifth axial ring ; as far as 
this point the deep axial furrows converge backwards at about thirty degrees, but 
beyond it, to the blunt tip, they are subparallel. The side-lobes are arched-down 
moderately and each carries five deep pleural furrows and a sixth, fainter furrow. 
The anterior half-rib is deflected ventrally to form a facet of only moderate size. 
Each of the remaining ribs carries an interpleural furrow which is only faint over most 
of its length (v.) but then forms a broad depression level with the abaxial ends of 
the adjacent pleural furrows and is directed obliquely backwards and outwards in 
relation to them. Although the specimen is incomplete there appears to be a 
smooth, narrow border. 


Discussion. Numerous species of Neseuvetus have been described, mostly from 
the Arenig and Llanvirn Series, and many of them have been discussed by Whittard 
(1960 : 138-151). Almost all can be separated from the new species by their 
possession of a so-called “ anterior boss ”’ in front of the glabella and their lack of a 
discrete preglabellar field, the only form possessing an apparently similar structure 
being Neseuretus birmanicus (Reed), a species now assigned to N. (Neseuretinus). 
This form was described from the Upper Naungkangyi Beds of Burma as Calymene 
birmanica by Reed (1906 : 71, pl. 5, fig. 27 ; 1915: 44, pl. 8, figs. 1-5), and although 
there is still uncertainty regarding the precise geological age it may not be far removed 
from that of the new Turkish species. More recently Lu (1957 : 288, pl. 154, figs. 1, 
2) has figured as Synhomalonatus (sic) biymanica a cranidium and pygidium from the 
“Middle Ordovician”’ of Yunnan. His illustrations are merely reproductions of 
two of Reed’s figures of 1915, but the record is interesting in that it extends the 
known geographical range of Neseuretinus into China. In the present state of 
knowledge of the age of the Burmese faunas it is not possible to say whether N. 
(N.) turcicus is younger than N. (N.) biymanicus, but it may easily be distinguished 
from the latter species by the more pointed and considerably longer anterior border, 
the more convex preglabellar field, and the slightly narrower glabella, Reed's 


118 ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 


paper (1915) shows that N. (N.) biymanicus possesses a pair of small paraglabellar 
areas, which were not apparent in the illustrations to his 1906 publication ; it is 
not yet clear whether corresponding structures are present in N. (N.) turcicus, but 
the appropriate portion of the cranidium has not been found well preserved. 


Family EOHOMALONOTIDAE Hupé, 1953 
Genus BRONGNIARTELLA Reed, 1905 
Brongniartella levis sp. nov. 

(Bl 8) stigs. 25 S60) 


Dracnosis. Large species of Brongniartella with gently convex cranidium and 
scarcely defined glabella. Cranidium notably broad frontally with frontal margin 
only slightly convex forwards. Three pairs unequal glabellar lobes almost indis- 
tinguishable. Palpebral lobes opposite third glabellar furrows and some distance 
from glabella. Large, poorly-defined paraglabellar areas present. 


Honotyre. It.12719. 


LOCALITY AND HORIZON. Locality B.18 in the section west of Bedinan. The 
horizon is in the highest part of the mudstone/shale succession of the Bedinan 
Formation. 


DeEscrRIPTION. The new species is represented with certainty by only a single 
incomplete, large cranidium of markedly depressed form. The median length is 
51 mm., whilst the basal breadth must have been of the order of 80 mm., although 
the outer parts are incomplete. The glabella is subtrapezoidal in outline with a 
length of 35 mm., narrowing forwards from a basal breadth of about 36mm. 
(estimated). The anterior and lateral margins are only poorly defined by furrows 
which are little more than broad, shallow indentations of the test. Glabellar 
lobation is almost indiscernible, in addition to being obscured by slight crushing of 
the test, but there are suggestions of three pairs of glabellar lobes of markedly 
unequal size, the basal pair being much the largest, occupying almost half the 
glabellar length. The second glabellar lobes are rather less than half the length 
of the basal pair, whilst the first pair are notably small, probably less than half the 
size of the second pair. There is a gentle, outwards curvature of the axial furrows 
opposite the second glabellar lobes, which project a little beyond the other pairs of 
lobes. The anterolateral angles of the glabella are slightly swollen dorsally to form 
a pair of low, lobe-like structures, between which the otherwise almost straight 
anterior margin of the glabella is slightly indented. Similar structures have been 
observed elsewhere in Brongniartella, Neseuretus, and other trilobites of the Calymen- 
acea. A slight, longitudinal, median ridging of the centre of the glabella, though 
probably exaggerated by crushing, is undoubtedly original in part, and represents a 
feature known from other species of Brongniartella. The preglabellar field and anterior 
border cannot be differentiated but are combined to form a broad (sag.), scoop-like 
structure which is moderately arched transversely, gently inclined forwards, and has 
its dorsal surface slightly concave, The border is separated by only a pair of shallow 


ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 119 


depressions from the anterior parts of the fixigenae, which are broad and gently 
declined abaxially. The anterior margin of the cranidium is broadly rounded in 
outline. The occipital ring is subrectangular in plan, its dorsal surface almost flat, 
whilst the occipital furrow is broad (sag.) and only lightly impressed, especially 
medially and abaxially where it is almost obsolete. It curves forwards slightly at 
its outer ends where the occipital ring passes almost imperceptibly into what remains 
of the posterior border. The palpebral lobes are set fairly well back, behind centre 
of the glabella and opposite the third glabellar furrows, and stand only slightly lower 
than the highest part of the cranidium. In plan they are moderately convex 
outwards, particularly well defined at their posterior ends, and carry no trace of 
palpebral furrows. The portions of the fixigenae behind the eyes are more steeply 
declined abaxially than are the anterior parts. They contain a pair of roughly 
quadrant-shaped paraglabellar areas which are large, extending forwards as far as 
the third glabellar furrows, but poorly defined by traces of shallow furrows. The 
facial suture is known from only the left anterior branch. This is sigmoidal in 
plan, at first curving forwards and slightly inwards from the eye, but then turning 
gently outwards until it reaches the cephalic border longitudinally almost in-line 
with the eye ; finally it sweeps inwards in a broad curve to meet the cephalic margin 
approximately level with the posterolateral corner of the glabella. The surface of 
the test is smooth except for the extreme edge of the anterior border, which is 
finely granulated. In addition there are widely-spaced, conspicuous pits on the 
fixigenae anterior to the eye, whilst similar punctae are grouped more closely on the 
anterior half of the frontal cephalic border, forming a zone parallel to the anterior 
margin. 

In addition to the holotype of Brongniartella levis, trilobite fragments assignable 
to the genus were found, though at other levels and localities, in the Bedinan Forma- 
tion south-west of Bedinan (see Pl. 8, figs. 1, 5). All represent smaller individuals 
than the holotype and none is sufficiently well preserved for certain identification. 
An incomplete cranidium (Pl. 8, fig. 1) may represent an immature individual of 
Brongmartella levis. A fragmentary thorax and pygidium (Pl. 8, fig. 5) appear 
typical for the genus but are insufficient for detailed comparison. 


Discussion. Brongniartella levis is one of a group of broadly comparable species 
of the genus occurring over a wide area in rocks belonging to the lower or middle 
parts of the Caradoc Series. In the Anglo-Welsh area Brongniartella caradociana 
Dean (1961 : 349), from the Costonian Stage [Nemagraptus gracilis Zone], is a 
slightly smaller species distinguished by having a more convex glabella, the anterior 
half of which becomes markedly narrower, and eyes set farther forwards than in the 
Turkish form. The well-known Brongniartella bisulcata M’Coy sp. (see Dean 
1961 : 346), from a Caradoc horizon roughly contemporaneous with that of B. 
levis, has the eyes a little farther forwards than the latter species, the sides of the 
glabella are less convergent forwards, and the cranidium is proportionately narrower 
frontally. Brongniartella platynota (Dalman) [= B. inexpectata Barrande sp., 
see Kielan 1960: 116] is a later form, apparently the last-known Brongniartella, 
widely distributed in the Ashgill Series of Central Europe and Scandinavia. It is 
easily distinguished from B. levis and other species of the genus by having the eyes 


120 ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 


set well forwards, whilst the glabellar outline narrows markedly and the front of 
the cranidium is narrower and more convex in plan. 


Genus PLAT YCORYPHE Foerste, 1919 
Platycoryphe? sp. 
(Pi Ss tie4) 

A single, small cranidium is tentatively assigned to Platycoryphe. The glabella 
has a basal breadth about one and a half times the median length (estd), there are 
three unequal pairs of glabellar lobes, and the outline narrows markedly in front of 
the second glabellar furrows. There is a suggestion of a right paraglabellar area but 
the eyes and the front of the cranidium are not preserved. 

The problems of separating Brongniartella and Platycoryphe have been discussed 
elsewhere (Dean 1961 ; Whittington 1965). In general, the glabella of Platycoryphe 
is the more strongly segmented, a feature found in the present specimen. The 
specimen is, however, preserved as an internal mould, in which all cephalic furrows 
tend to appear deeper, and from the position of the glabellar furrows one cannot 
exclude the possibility of its being an immature example of Brongniartella levis. 
In the absence of the anterior border it seems better to refer the specimen, with some 
doubt, to Platycoryphe. 

LocaLITty AND HORIZON. Locality B.20, in the Bedinan Formation west of 
Bedinan. The horizon is very close to others containing Brongniartella and the 
only other place where the two genera occur together is in South Shropshire, in 
the lowest subdivision of the Caradoc Series (Dean 1961). 


Family COLPOCORYPHIDAE Hupé, 1953 
Genus COLPOCORYPHE Novak in Perner, 1918 
Colpocoryphe sp. 

(Pl. 9, figs. 5, 6-10) 

This characteristically Mediterranean genus is represented in the Bedinan faunas 
by only three specimens, one reasonably complete and two fragmentary cranidia. 
The glabella seems relatively narrow for the genus, with a long, transversely rectan- 
gular, frontal glabellar lobe, and the axial furrows converge forwards only gently. 
The Turkish species, which may be new, is probably the youngest member of the 
genus yet recorded. Colpocoryphe grandis Snajdr sp. (1956: 501, pl. 3, figs. 1-9), 
from the Drabov and Letna Beds (low Caradoc Series) of Bohemia, is broadly similar 
and has the eyes in a corresponding position, but differs in having more convergent 
axial furrows and a smaller, shorter frontal glabellar lobe. 

FIGURED SPECIMENS. It.1183 (PI. 9, fig. 5); It.1197 (Pl. 9, figs. 6-8, 10); It.1204 
(Pio tie. 10): 

LOCALITIES AND HORIZONS. One specimen is from locality A.3, east of Sosink, 
whilst the others are from B.1 and B.2, south-west of Bedinan. All these localities 
are believed to be in the lower part of the Bedinan Formation, and Colpocoryphe 
is one of the trilobites common to both sections, 


ORDOVICIAN TRILOBITE FAUNA OFS.E. TURKEY 121 


Family ODONTOPLEURIDAE Burmeister, 1843 
Subfamily SELENOPELTINAE Whittington, 1956 
Genus SELENOPELTIS Hawle & Corda, 1847 
Selenopeltis inermis (Beyrich) angusticeps subsp. nov. 
(Piro figsame 4) 62,7, 8) 

DiaGnosis. Subspecies of S. mermis characterized by having narrower glabella, 
with sides only slightly convex in plan. Eyes set less far apart than in S. inermis, 
and palpebral lobes less convex abaxially in plan. Frontal glabellar lobe has forked 
appearance owing to median depression extending backwards as far as second 
glabellar furrows. 

IW@EOTYPE.. It.1195 (PI. 10, figs. 4, 7, 8). 

LOCALITIES AND HORIZONS. The holotype is from locality A.2 in the section east 
of Sosink, whilst a small pygidium probably attributable to the same subspecies 
(see Pl. ro, fig. 6) was found nearby, at locality A.3. The only other specimen 
belonging, probably, to S. inermis angusticeps, is a fragmentary thorax (Pl. Io, 
fig. 1) from locality B.1, south-west of Bedinan. All these localities are believed to 
occur within the lower part of the Bedinan Formation. 

DESCRIPTION. Selenopeltis inermis is a well-known species, widely distributed in 
Europe and the Mediterranean (Tethyan) Province, and its various subspecies 
extend with only relatively small modifications from the Arenig to Ashgill Series. 
Beyrich (1846: 20, pl. 3, figs. 2a-c) first described S. inermis from “ Wessela”’, 
Bohemia, whilst the lectotype of Selenopeltis buchi (Barrande 1846: 28), a species 
considered by Whittard (1961: 197) to be a subjective synonym of S. inermis, 
came from the Chlustina Beds (Caradoc Series) of Zahotany, Bohemia (see Snajdr 
1956:501). The holotype cranidium of S. imermis angusticeps is broadly comparable 
with published illustrations of the Bohemian species but may be distinguished by the 
features listed in the diagnosis. In particular the glabellar sides of the Turkish 
form appear almost straight by comparison, whilst the distance from the palpebral 
lobe to the axial line is conspicuously less than in the Czech specimens. The 
fragment of thorax from east of Sosink shows no diagnostic features but the small 
pygidium from near Bedinan, although close to that of S. eermis inermis, appears to 
be slightly longer and has a median indentation of the margin. However, this 
specimen is too poorly preserved for detailed comparison and neither it nor the 
thoracic fragment is included as type material. S. inermis angusticeps is not yet 
known from anywhere but the Sosink—Bedinan region but it is interesting to note 
that Seilacher (1963 : 530, fig. 2) has recorded Selenopeltis bucht from the Sinat Shales 
in northernmost Iraq, not far to the east of the Turkish outcrops. 


Family ASAPHIDAE Burmeister, 1843 
Asaphid gen. et sp. indet. 


(Pl. ro, figs. 2, 5) 


A single hypostoma, figured here as an internal mould and a latex cast of the 
corresponding external mould, is the only evidence of asaphid trilobites yet known 


122 ORDOVICIAN DRILOBIDE FAUIN ATOR Se UKE 


from the Bedinan Formation. The maximum breadth, measured almost across the 
centre, is estimated as about three-quarters of the maximum length. The overall 
outline is suboval but the posterior margin is bifid, with a large, parabolic, median 
indentation extending for about one quarter of the length of the entire hypostoma. 
There isa large, subcircular, median lobe of low convexity, circumscribed by a furrow 
which is deepest posterolaterally. The median lobe is separated from the apex of 
the median indentation by a narrow (sag.), flat strip equal to about one tenth of the 
total length of the hypostoma, and ending laterally in a pair of poorly-defined 
maculae. Although the front of the hypostoma is incomplete, and there is no trace 
of anterior wings, there is a flattened lateral border, bearing terrace-lines on its 
dorsal surface, which is continuous with the bifurcated posterior border. 


FIGURED SPECIMEN. It.1203. 


LOCALITY AND HORIZON. Locality A.6, east of Sosink, the highest fossiliferous 
horizon in this particular section. 


Vil. REPERENCES 

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ORDOVICIAN TRILOBITE FAUNA OF S.E. TURKEY 123 


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EXPLANATION OF PLATES 
All the specimens are from the Bedinan Formation and are housed in the British 
Museum (Natural History), the registration numbers bearing the prefix It. They 
are preserved as internal or external moulds, the latter usually being figured in the 
form of latex casts. A light coating of ammonium chloride was applied before 
photographing. Plates 1 to 4 by the writer; Plates 5 to 10 by Mr. P. J. Green. 


IIL INI 1, 
Marrolithoides orthogonius sp. nov. p. 96 
Bedinan Formation, locality A.3, east of Sosink. 


Fic. 1. Latex cast of cranidium. Paratype, It.812, x5. 
Fic. 2. Left half of internal mould of small cranidium. Paratype, It.803, x9. 
Fic. 3. Ventral side of internal mould of cephalon showing girder. Paratype, It.819, x4. 


Fic. 5. Right side of cranidium showing anterolateral angulation of outline, with small, 
marginal projection at about R16. It.806, x8. 

Fic. 6. Internal mould of cranidium. Holotype, It.1200, x3. 

Fic. 7. Cranidium (Meraspis, Degree unknown) showing only two frontal rows of pits, 
increasing to three at R2 and four at about Rg. Note the alar lobes and eye-ridges. Paratype, 
It.762, X15. 

Fic. 9. Internal mould of dorsal exoskeleton, Meraspis Degree 4. Paratype, It.818, x8. 


Bedinan Formation, locality A.6, east of Sosink. 


Fic. 4. Group of three individuals, one enrolled, preserved as internal moulds. Paratype, 
It.747, X4. 

Fic. 8. Internal mould of cranidium. Note also cranidium of small Meraspis to right, and 
pedicle valve of a brachiopod, Aegivomena, in top left corner. Paratype, It.749, x6. 


Buil. Br. Mus. nat. Hist. (Geol.) 15, 2 PLATE 1 


GEOL. I5, 2. 


PLATE 2 
Marrolithoides laticirrus sp. nov. p. 99. 
Bedinan Formation, locality B.3, south-west of Bedinan. 
Fic. «. Internal mould of thorax and pygidium, with external mould of left half of cephalic 
fringe. Paratype, It.707, x3. 

Fic. 3. Internal mould of small cranidium. Paratype, It.706, x8. 
Fic. 5. Latex cast of cephalon with left librigenal spine. Holotype, It.683, x3. 
Fic. 11. Internal mould of incomplete cranidium. Paratype, It.690, x5. 
Fic. 13. Latex cast of cranidium. Paratype, It.708, x4. 
Fic. 14. Latex cast of small cranidium. Paratype, It.712b., x6. 


Bedinan Formation, locality B.4, south-west of Bedinan. 


Fic. 9. Latex cast of small cranidium showing frontal arrangement of fringe pits. It.738b., 
x6. 


Cryptolithus? cf. inferus sp. nov. p. 102. 
Bedinan Formation, locality B.2, south-west of Bedinan. 


Fic. 2. Internal mould of thorax and pygidium. It.704, x3. 
Fia. Part of cephalic fringe, showing girder. It.703, x4. 
Fic. Latex cast of small cranidium. It.697, x4. 


Sap 


Bedinan Formation, locality B.3, south-west of Bedinan. 
Fic. 12. Internal mould of cranidium. It.689, x4. 


Cryptolithus? inferus sp. nov. p. 102. 
Bedinan Formation, locality B.1, south-west of Bedinan. 
Fic. 6. External mould of ventral side of fringe. Paratype, It.735, x2. 


Fic. 8. Latex cast of cranidium. Holotype, It.734, x3. 
Cryptolithus? sp. p. 107. 


Bedinan Formation, locality B.6, south-west of Bedinan. 


Fic. 10. Internal mould of pathological cranidium with abnormally irregular arrangement of 
pits frontally. It.1232, x3. 


PATE 2 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 2 


SOL 


os A 


™ 
*y 
j 


t 


13§ 


GEOL. I5, 2. 


PLATE 3 
Cryptolithus? bedinanensis sp. nov. p. 104 
Bedinan Formation, locality B.6, south-west of Bedinan. 


Fic. 1. Internal mould of cranidium, It.663, x4. This is one of the earliest, rare members 
of the species to have 4 frontal rows of pits. 

Fics. 2, 3. Oblique posterolateral and plan views of internal mould of dorsal exoskeleton. 
Holotype, It.1210, 6, shows blunt pleural tips. Fig. 3, x4. 

Fic. 6. Latex cast of two small individuals, probably Meraspis, Degree 5. Paratype, 
It.1211, X5. 

Fic. 9. Internal mould of incomplete cranidium. Paratype, It.1231, x5. 


Bedinan Formation, locality B.10, west of Bedinan. 


Fic. 4. Internal mould of cranidium. It.713, x3. 
Fic. 7. Internal mould of ventral side of fringe, showing almost equal development of girder 
and two pseudogirders. It.715, x3. 


Bedinan Formation, locality B.15, west of Bedinan. 
Fic. 5. Latex cast of cranidium. It.856, x3. 


Cryptolithus? sp. juv. p. 107 
Bedinan Formation, locality B.8, south-west of Bedinan. 


Fic. 8. Latex cast of cranidium of small Meraspis [Degree unknown], showing only two 
concentric rows of pits both frontally and laterally. It.718, x15. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 2 


op eat 4 
Send 


ih IP Radel A 


rE 
Riera! 
‘ = 


PEATE 
Cryptolithus? cf. bedinanensis sp. nov. p. 107 
Bedinan Formation, locality B.13, north-west of Bedinan. 


Fic. 1. Pathological cranidium in which the regular pit arrangement is disturbed in front of 
the right axial furrow. It.837, x3. 


Cryptolithus? bedinanensis sp. nov. p. 104 
Bedinan Formation, locality B.12, north-west of Bedinan. 


Fic. 2. Latex cast of underside of fringe, showing principal girder and two weaker pseudo- 
girders. It.836, x3. 
Fic. 3. Internal mould of cranidium. It.834, x4. 


Bedinan Formation, locality B.16, north-west of Bedinan. 
Fic. 4. Internal mould of cranidium with four rows of pits developed frontally. It.867, x3. 


Bedinan Formation, locality B.22, south-east of Bedinan. 
Fic. 5. Latex cast of small cranidium. It.890, x6. 


Bedinan Formation, locality B.13, north-west of Bedinan. 


Fic. 6. Internal mould of incomplete cranidium. It.1212, x3. 

Fic. 7. Internal mould of cranidium. It.1216, x3. 

Fic. 8. Internal mould of cranidium with two attached thoracic segments. It.1215, x3. 

Fic. 9. Internal mould of small cranidium showing reticulation of the cheek-lobes. It.1214, 
5 


Marrolithoides sp. p. Ior 
Bedinan Formation, locality B.21, north-west of Bedinan. 


Fic. 10. Internal mould of cranidium. Note long occipital spine and anterolateral angulation 
of cephalic outline. It.881, x3. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 


PLATE 5 
Dionide formosa (Barrande) anatolica subsp. nov. p.109 
Bedinan Formation, locality A.3, east of Sosink. 

Fics. 1,2. Plan and left oblique views of cranidium showing long glabellar spine. Holotype, 
It.1061, X4. 

Fic. 3. Plan view of specimen showing left librigenal spine and part of thorax. Note 
macropleural first segment. Paratype, It.1201, x5. 

Fic. 12. Internal mould of pygidium illustrating hindmost pleural ribs. Paratype, It.1057, 
x4. 


Bedinan Formation, locality A.6, east of Sosink. 
Fic. 4. Latex cast of cranidium. Paratype, It.1178, x7. 


Bedinan Formation, locality A.5, east of Sosink. 


Fic. 6. Internal mould of cranidium. Paratype, It.1062, x6. 
Fic. 7. Internal mould of pygidium with thorax lacking first segment. Paratype, It.1063, 
x6. 


Ampyx nitidus sp. nov. p. 93 
Bedinan Formation, locality B.2, south-west of Bedinan. 


Fic. 
Fic. 
Fic. 
Fic. 
Fic. 


Internal mould of pygidium. Paratype, It.1207, x4. 

Internal mould of cranidium. Holotype, It.1181, x3. 

Fragment of right cheek showing position of eye. Paratype, It.1208, x4. 

o. Internal mould of small hypostoma. Paratype, It.1180, x12. 

1. Incomplete cranidium showing faint glabellar lobes. Paratype, It.1209, x3. 


Lat el CIs 


Bull. Bry. Mus. nat. Hist. (Geol.) 15, 2 PAE 5 


PLATE 6 
Dalmanitina proaeva proaeva (Emmrich) p. 112 
Bedinan Formation, locality B.21, west of Bedinan. 


Fic. 1. Internal mould of cephalon. It.1224, 1-5. 
Fics. 4, 11. Latex cast and internal mould of pygidium. It.1226, x2. 


Bedinan Formation, locality B.13, west of Bedinan. 
Fic. 2. Plan view of pygidium. It.1190, x3. 


Bedinan Formation, locality B.20, west of Bedinan. 
Fics. 3, 5. Internal mould of pygidium. It.1222, x2. 


Bedinan Formation, locality B.3, west of Bedinan. 


Fic. 6. Internal mould of slightly disarticulated specimen. It.1186, x2°5. 
Fic. 7. Internal mould of small hypostoma. It.1185, x3. 


Bedinan Formation, locality B.19, west of Bedinan. 


Fics. 8 12. Plan and posterior views of internal mould of pygidium. It.1193, x1. (See 
also Pl. 7, fig. 5.) 


Bedinan Formation, locality B.z2, west of Bedinan. 
Fic. 9. Internal mould of slightly compressed hypostoma. It.1182, x2. 


Bedinan Formation, locality B.22, west of Bedinan. 
Fic. 13. Internal mould of cephalon and pygidium with long terminal spine. It.1233, 1-5. 


Kloucekia phillipsii (Barrande) euroa subsp. nov. p. 113 
Bedinan Formation, locality B.13, south-west of Bedinan. 


Fic. 10. Plan view of internal mould of pygidium with thorax attached. Holotype, It.1188, 
x3. (See also Pl. 7, figs. 9, 12.) 


PLATE 6 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 2 


PLATE 7 
Kloucekia phillipsii (Barrande) ewroa subsp. nov. p. 113 
Bedinan Formation, locality B.21, west of Bedinan. 


Fic. 1. Internal mould of incomplete cephalon. Paratype, It.1225, x2. 
Fic. 2. Plan view of internal mould of cephalon. Paratype, It.1223, x4. 


Bedinan Formation, locality B.13, south-west of Bedinan. 


Fic. 3. Internal mould of almost complete dorsal exoskeleton. Paratype, It.1189, X1°5. 

Fics. 6, 7. Plan and oblique ventral views of cephalon. Fig. 7 shows doublure and vincular 
furrow. Paratype, It.1187, x3. 

Fics. 9,12. Thorax with attached pygidium (see also Pl. 6, fig. 10). Holotype, It.1188, x2. 


Dalmanitina proaeva proaeva (Emmrich) p. 112 
Bedinan Formation, locality B.3, south-west of Bedinan. 


Fic. 4. Latex cast of cranidium of Meraspis (Degree unknown). It.1018, x12. 


Bedinan Formation, locality B.19, west of Bedinan. 


Fic. 5. Latex cast of pygidium with exceptionally long terminal spine. It.1193, XI. 
(See also Pl. 6, figs. 8, 12.) 


? Neseuretus (Neseuretinus) turcicus subgen. et sp. nov. p. 117 
Bedinan Formation, locality A.3, east of Sosink. 


Fics. 8, 10, 11. Posterior, plan and right lateral views of internal mould of pygidium. 
It.1196, <2. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 2 PLATE 7 


PLATE 8 
Brongniartella sp. p. 119 
Bedinan Formation, locality B.13, south-west of Bedinan. 
Fic. 1. Internal mould of damaged cranidium. It.1217, X1°5. 


Bedinan Formation, locality B.19, south-west of Bedinan. 
Fic. 5. Internal mould of thorax and pygidium. It.1220, X2°5. 


Brongniartella levis sp. nov. p. 118 
Bedinan Formation, locality B.18, south-west of Bedinan. 


Fics. 2, 3,6. Anterior, left lateral and plan views of incomplete, large cranidium. 


It.1219, X1-25. 


Platycoryphe ? sp. p. 120 
Bedinan Formation, locality B.20, south-west of Bedinan. 
Fic. 4. Internal mould of incomplete cranidium. It.1221, <3. 


Holotype. 


PLATE 8 


Bull. Br. Mus. nat. Hist. ( 


PLATE 9 
Neseuretus (Neseuretinus) turcicus subgen. et sp. nov. p. 115 
Bedinan Formation, locality B.2, south-west of Bedinan. 


Fies. 1-3. Plan, left lateral and oblique anterolateral views of latex cast of incomplete 
cranidium, showing convex preglabellar field and large, inclined, anterior border. Holotype, 
It.1179, <3. 

Fic. 4. Plan view of internal mould of incomplete cranidium lacking marginal portion of 
anterior border. Paratype, It.1205, x2. 


Colpocoryphe sp. p. 120 
Bedinan Formation, locality B.2, south-west of Bedinan. 
Fic. 5. Latex cast of frontal portion of fragmentary cranidium. It.1183, x2. 


Bedinan Formation, locality A.3, east of Sosink. 


Fics. 6, to, latex cast and figs. 7, 8, corresponding internal mould, of small cranidium. 
It.1197, X06. 


Bedinan Formation, locality B.1, south-west of Bedinan. 
Fic. 9. Posterior half of glabella, an internal mould. It.1204, x2°5. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 2 PLATE 9 


PLATE to 
Selenopeltis inermis (Beyrich) angusticeps subsp. nov. p. 121 
Bedinan Formation, locality B.1, south-west of Bedinan. 
? Fic. 1. Internal mould of fragment of thorax. It.1206, x2°5. 


Bedinan Formation, locality A.2, east of Sosink. 


Fics. 4,7, 8. Left lateral, anterior and plan views of internal mould of cranidium. Holotype, 
It.1195, X3. 


Bedinan Formation, locality A.3, east of Sosink. 
? Fic. 6. Internal mould of small pygidium. It.1198, x5. 


Asaphid gen. et sp. ind. p. 121 
Bedinan Formation, locality A.6, east of Sosink. 


Fies. 2,5. Latex cast and internal mould of hypostoma, showing indented posterior margin. 
It.1203, X25. 


Cheirurid gen. et sp. ind. p. 114 
Bedinan Formation, locality B.12, south-west of Bedinan. 


Fic. 3. Latex cast of left half of thoracic segment, showing furrow with pits, and anterior 
flange terminating in articulating process. It.1213, 2°5. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 2 PLATE to 


PRINTED IN GRE 
BY ADLARD & s 
BARTHOLOME 


BURROWS AND SURFACE TRACES 
_ FROM THE LOWER CHALK OF 
SOUTHERN ENGLAND 


W. J. KENNEDY 


3 BULLETIN OF 

a THE BRITISH MUSEUM (NATURAL HISTORY) 
_ GEOLOGY Vol. 15 No. 3 

: LONDON: 1967 


DOR ROWS AND SURFACE TRACES FROM THE 
LOWER CHALK OF SOUTHERN ENGLAND 


BY 
WILLIAM JAMES KENNEDY 


Pp. 125-167; 9 Plates; 7 Text-figures 


BULLETIN OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 


GEOLOGY Vols No: 3 
LONDON: 1967 


THE BULLETIN OF THE BRITISH MUSEUM 
(NATURAL HISTORY), istituted im 1949, 1s 
issued in five series corresponding to the Departments 
of the Museum, and an Historical series. 


Parts will appear at irregular intervals as they become 
veady. Volumes will contain about three or four 
hundred pages, and will not necessarily be completed 
within one calendar year. 

In 1965 a separate supplementary series of longer 
papers was instituted, numbered serially for each 
Department. 

This paper is Vol. 15, No. 3 of the Geological 
(Palaeontological) series. The abbreviated titles of 
periodicals cited follow those of the World List of 
Scientific Periodicals. 


World List abbreviation : 
Bull. Br. Mus. nat. Hist. (Geol.). 


© Trustees of the British Museum (Natural History) 1967 


TRUSTEES OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 


Issued 24 November, 1967 Pricer i2meese 


meRKkOWS AND SURFACE TRACES FROM THE 
LOWER-CHALK OF SOUTHERN ENGLAND 


By WILLIAM JAMES KENNEDY 


CONTENTS 
Page 
I. INTRODUCTION : : ‘ : : > : j : 127 
II. THE TRACE FOSSILS : 6 : é c : ‘ : 130 
III. Location OF SPECIMENS . : : 0 : 5 ; : 131 
IV. SYSTEMATIC DESCRIPTIONS c 0 0 9 : : 6 131 
V. OTHER BURROWS . ‘ . : : . 3 ; : 156 
VI. CONCLUSIONS : ; c : é : : : : 161 
VII. AcKNOWLEDGMENTS ; : : : : F : : 162 
VIII. REFERENCES. ‘ : : : é : : : : 162 
SYNOPSIS 


The Lower Chalk of Southern England comprises between 17 and 80 m. of rhythmic alterna- 
tions of more or less calcareous marly chalk. The whole sequence is intensely burrowed, the 
following burrow types are named: Thalassinoides saxonicus (Geinitz), T. cf. suevicus (Rieth), 
T. ornatus ichnosp. nov., T. pavadoxica (Woodward), Spongeliomorpha sp., Spongeliomorpha? 
annulatum ichnosp. nov. and Chondrites sp. Several other forms are discussed, including “‘ Teve- 
bella’’ cancellata Bather and Keckia (?) sp. -Five burrow types too poor for detailed description 
are noted and discussed. Two other trace-fossils, ‘‘ laminated structures ’’, regarded as related 
to T. saxonicus and Pseudobilobites jefferiesi ichnosp. nov. (the “ problematicum ”’ of Jefferies 
(1961, 1963)) are also described. 

The Eocene form “‘ Tevebella’’ harefieldensis White is briefly discussed and interpreted as a 
crustacean boring. Thalassinoides, Spongeliomorpha “laminated structures ’’, Pseudobilobites, 
“ Terebella’”’ cancellata and two of the un-named burrows are regarded as the product of crusta- 
ceans, Chondyvites and the other un-named burrows are attributed to ‘“‘ worms ”’. 

Other trace fossils—borings and micro-coprolites-are also noted. 


I. INTRODUCTION 
(a) GENERAL FEATURES. The Lower Chalk of Southern England comprises between 
17 and 80 m. of marly blue or buff chalk, ranging in age from Lower to Upper Ceno- 
manian. The present account is based chiefly on exposures along the North and 
South Downs, the Chilterns and the Isle of Wight, although sections to the north, 
at Hunstanton (Norfolk) and south-west (Dorset, Somerset and Devon) have also 
been examined. 

Apart from the valuable coastal exposures, there are useful working sections around 
Lewes (Sussex), Burham and Holborough in the Medway Valley (Kent) and in the 
large pits at Barrington (Cambridgeshire), Houghton Regis and Totternhoe (Bed- 
fordshire), Pitstone (Buckinghamshire), Chinnor and Childrey (Oxfordshire). 

By far the best general account of the formation is still that given by Jukes-Browne 
(1903), whilst a brief outline of some of the depositional and post-depositional 
features has been given elsewhere (Kennedy, 1967). 

GEOL. 15, 3. 14 


128 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


In the Weald, Hampshire and the Chilterns, the base of the formation is generally 
marked by a sharp lithological break and a line of piping, the basal Glauconitic Marl 
being let down into the Gault or Upper Greensand below, generally without signs of 
marked erosion, and with occasional indications of continuous deposition from the 
Albian below. The basal few feet, rich in glauconite and phosphates, clearly indi- 
cates slow deposition; similar features appear occasionally in the lower part of the 
Chalk Marl above, as at Eastbourne (Sussex) and in the Isle of Wight. Above, 
the whole thickness can be interpreted as a sequence of rhythmic alternations of more 
and less calcareous (or marly) chalks, with carbonate contents varying between 
approximately 40% at the base, increasing upwards to 90-95% at the top of the 
Lower Chalk. Insoluble residue determinations suggest that these rhythms are 
visible when the difference in carbonate content is as low as 4-5 %. 

There is much variation in thickness of the “ limestone ’”’ and “ marl ’’ members 
of rhythms, although in a general way, in the lower part the “ marls”’ are 45-60 cm. 
thick, the “‘ limestones ”’ 15-30 cm. thick. In the middle part the alternations are 
15-30 cm. thick, whilst in the upper part, there is great variation, made difficult to 
interpret by the low mud content which renders the alternations only faintly discern- 
ible. A general, although not invariable feature of these rhythms is that the “ marl” 
to “limestone ”’ contact is transitional, whilst the contact at the base of the marls is 
very sharp. 

The following features indicate that the alternations are, at least in part, primary: 


(i) The piping of “‘ marls”’ into “ limestones ”’ and vice-versa, in a wide variety 
of burrows. 


(ii) The occurrence of “‘limestone’”’ pebbles, phosphatized, glauconitized and 
otherwise, in “‘ marls’’. 


(ii1) The cutting of ‘‘ marl ’’—“ limestone ”’ junctions by erosion hollows. 


Evidence of secondary segregation is suggested by the nodular appearance of 
some “‘ limestones’ and the occurrence of calcareous concretions in some of the 
“marls’”’. In addition, sponges, ammonites and other fossils in “ limestones ”’ are 
often undistorted whilst the same forms are crushed flat in “‘ marls’’, suggesting the 
pre-compactional deposition of carbonate in the more calcareous parts of rhythms. 

The upper limit of the Lower Chalk in this region is marked by a sharp change in 
lithology at the base of the plenus Marls, associated in some areas with obvious signs 
of erosion, the sub-flenus erosion surface of Jefferies (1962, 1963). 

Traced northwards, the Lower Chalk loses these features, thins considerably and 
in Norfolk at Hunstanton is clearly condensed, with signs of erosion at many levels. 
It rests, with a sharp break and obvious signs of erosion on the Red Chalk (Albian). 
The Chalk here is hard, and as pointed out by Peake & Hancock (1961) probably 
winnowed. These features, and a similar thinning and condensation in the under- 
lying Albian suggest the presence of a stable massif in this region during part, at least, 
of the Cretaceous. The influence of this massif may, in part be responsible for the 
development, in the Chilterns and northwards, of the “ gritty ’’ phosphatic Tottern- 
hoe Stone (Middle Cenomanian). 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 129 


Traced westwards, the Lower Chalk maintains its general features to the western 
limits of outcrop at Membury (S. Devon), where rhythms are still present in the 
chalky part of the sequence. Faunal evidence indicates that the base of the Chalkis 
diachronous in the south-west. 


(b) THE CHALK. The general composition of the Chalk was first noted by Ehren- 
berg (Sorby 1861) and later by Sorby (1861), Hume (1893) and Jukes-Browne & 
Hill (1903, 1904). More recently Black (1953), Black & Barnes (1959) and Hancock 
(1963) have given additional information. The carbonate portion of the Chalk is 
now wholly calcite, and it is generally accepted that most was deposited as such, and 
that it is wholly biogenic in origin. The finer fractions are largely composed of 
coccoliths, both whole and fragmentary, whilst the coarser fractions consist of Oligo- 
stegina, foraminifera, sponge fragments, the broken-down prismatic layers of 
Inoceramus and echinoderm debris. Abundance of the latter gives rise to the 
“ eritty ”’ chalks such as the Totternhoe Stone and Melbourn Rock. The insoluble 
fraction, discussed previously by Hume (1893) and Hill (1903, 1904) includes, in 
addition to the clay fraction, detrital silt and sand grade quartz as the most obvious 
mineral, accompanied by authigenic glauconite, collophane and feldspar. 


(c) Borrom ConpiTions. Current activity is indicated by the presence at many 
levels of winnowed chalks and rolled, glauconitized and phosphatized pebbles and 
fossils. The body chambers of large ammonites are often full of small fossils, includ- 
ing ammonites up to 10 cm. in diameter, presumably swept in by bottom currents. 
Fragmentation of /noceramus shells and echinoid tests may be due to current activity. 

Intraformational conglomerates suggest local erosion, as do what appear to be 
large scour hollows, sometimes associated with large ammonites (Kennedy, 1967). 

The presence of burrowing bivalves such as Pholadomya, Cucullaea, and Panopea 
suggest soft bottoms, as does the presence of Tevedina amp/isbaena (Goldfuss), a 
form which I have never seen associated with wood (although Tevedo bored wood 
occurs). Like the recent Tevedo (Furcella) polythalamia (Linné) (Oosting 1925) this 
form appears to have livedin mud. Although soft, the bottoms must have been in 
the form of a stiff mud, since the small solitary corals and serpulids which are so 
common would not survive in a fluid mud, nor would larger epifaunal forms such as 
the limid and pectinid bivalves and Inoceramus, the latter possibly byssally attached 
to the sea floor. Equally, the lobster-like crustacean Enoploclytia presumably 
needed a firm bottom to walk across. Intense burrowing suggests bottoms rich in 
organic debris. 

There is little evidence of rock bottoms (hardgrounds) in the Lower Chalk, erosion 
surfaces, when they occur, lacking the epifauna of bryozoa, serpulids and cemented 
bivalves present on the Chalk Rock hardgrounds. Borings in, and epifaunas on, 
the phosphatized top of the Upper Greensand in the south-west indicate hard bottoms 
here at least. 


(d) DeptH oF Deposition. The abundance of coccoliths suggests deposition 
below the upper limit of present day coccolith abundance (60 m.): study of the 
sponges indicates a depth of 280 m. (Cayeux 1897: Turonian—Senonian) or 300 m. 
(Gignoux 1926: Campanian). Since it is generally agreed that the Chalk Marl, like 


130 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


the Chalk Rock (U. Turonian) represents shallower conditions than the rest of the 
Chalk (Jukes-Browne & Hill 1904),a depth lower than the maximum is implied for 
this part of the Lower Chalk. Burnaby (1962) has discussed depth variation in the 
Lower Chalk sea, on the basis of the foraminifera. 


TE foe DRACE HOSStTes 
Two types of trace fossil are described from the Lower Chalk; burrows and surface 
traces. Of these, burrows are by far the most important, and are one of the most 
prominent features of the sediment (Pls. 1, 2). 


(a) Burrows. In modern marine environments a great variety of organisms 
utilize the region below the sediment—water interface for refuge, nourishment and 
habitation. Arthropods, echinoderms, molluscs, coelenterates, many groups of 
worms (particularly annelids) are amongst the most important groups of inverte- 
brates, whilst many higher animals burrow. In addition, the interstitial fluid be- 
tween sedimentary particles supports a large fauna and flora (Purdy, 1964). Particles 
of sediment themselves have a coating of bacteria, utilized by detritus feeders; total 
content increasing as particle sizes decrease (Newell 1965). 

The influence of these organisms on the sediment is considerable. Davidson (1891) 
described the activities of lobworms in the Holy Island Sands, between Holy Island 
and the Northumberland coast, suggesting nearly two thousand tons of sand was 
ingested per acre per annum, and that the top 60 cm. of sediment passed through the 
worms’ bodies every 22 months. Taylor (1964) quotes data suggesting 80-90% 
of the sands in the Bermudas is made up of ground shell matter that has passed 
through the intestinal tracts of echinoderms. Both indicate the importance of 
biological destruction of sedimentary structures. Local topography can be influenced 
by burrowing organisms; the hummocky bottom topography of the Bahaman 
platforms is attributed to organic activity (Taylor 1964), whilst erosion of callianassid 
burrows produces the characteristic sand-pipe topography of some intertidal regions 
(Weimer & Hoyt 1964). Many of the problematic mounds and depressions seen in 
deep-sea photographs are probably organic in origin. 

Many burrows are lined with mucus, whilst Callianassa major Say lines its burrow 
with collophane-cemented sand pellets (Weimer & Hoyt 1964). Many sediment 
eaters form durable faecal pellets (Moore 1939). These features indicate the im- 
portance of burrowing organisms in stabilization and aggregation of sediments. 

Taylor (1964) has pointed out the chemical effects of bottom dwelling organisms on 
both Eh and pH, particularly where the release of organic and inorganic acids is 
concerned, suggesting great importance in diagenesis at the early burial stage. 

Burrowers are also responsible for the creation of refuges for many commensals. 
The burrow of the worm Urechis, for instance, is inhabited by a gobie, polynoid worm 
and pinnotherid crab (Fisher & MacGinitie 1928). Dales (1957) gives details of 
similar associations in other burrowing organisms. 


(b) BURROWS IN THE LOWER CHALK. The whole of the Lower Chalk studied is 


intensely burrowed (PI. 2, figs. 2-4), often many times over (PI. 2, fig. 4). In general, 
these structures can be studied in section only, in the form of sedimentary mottling. 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 131 


Only rarely can the pattern and form of systems be made out. Burrowing, often 
equally intense to that in the Lower Chalk, can be seen, in suitable lithologies, in the 
overlying Middle and Upper Chalk. 

Simpson (1957), Hantzschel (1962) and Seilacher (1964) have discussed the various 
conditions of preservation of trace fossils; in the Lower Chalk the following modes of 
preservation of burrows can be distinguished: 


(i) Differences in composition and colour of burrow filling and matrix. 
(ii) Pyritization (an example of a pyritized burrow, overgrown by a pyrite nodule 
was figured by Mantell (1822, pl. 16, fig. 16)). 
(ii) Coating of the outer surface of the burrow by iron sulphide (often altered to 
Limonite), perhaps influenced by the former presence of a mucus lining. 


Burrowing in the English chalk has been mentioned only briefly by previous 
authors, generally as “‘ mottling ” or “ piping ’’, or by reference to them as sponges 
(Webster 1814) or “‘ Zoophytes”’ (Taylor 1823). More recently, Wood (1965), 
discussing the Lower Chalk at Dover, mentions “‘ extensive reworking ”’ by “ bottom 
living organisms, the infilling of the burrow traces being a lighter colour than the 
main mass of the sediment ”’. 

The only previous work on trace-fossils from the Lower Chalk is that of Davies 
(1879) and Bather (1911). The terebellids described by these authors are, in part, 
burrows, whilst the latter described a single fragment referred to as Keckia (?) sp. 


III. LOCATION OF SPECIMENS 
The author’s collection and the types of “‘ Terebella’”’ cancellata Bather and “ T.”’ 
harefieldensis White are in the collections of the British Museum (Natural History), 
Dr. R. P.S. Jefferies’ collection is in the Sedgwick Museum, Cambridge. These are 
abbreviated to B.M. (N.H.), and S.M.C. respectively in the following account. 


IV. SYSTEMATIC DESCRIPTIONS 


Ichnogenus THALASSINOIDES Ehrenberg 1944 


TYPE spEcIES. By the original designation of Ehrenberg (1944) Thalassinoides 
callianassae Ehrenberg, from the Miocene (Burdigalian) of Burgschleinitz, Eggenberg, 
Austria. 


Discussion. This trace fossil genus was erected for a ramifying system of cylindri- 
cal burrows from Miocene sands, intimately associated with, and probably formed by 
crustaceans (identified as Callianassa sp.) described by Ehrenberg six years previously 
(1938). The original diagnosis is as follows: “‘ Die Gattung ,,7halassinoides “‘ ware 
wie folgt zu kennzeichnen: Gange und Gangsysteme oder bzw. deren Ausfitillungen 
(Kerne) mit mehr oder weniger Y-formigen Gabelungen oder Verzweigungen, meist 
ohne wesentliche Oberflachenskulpturen: sonstige Form und Durchmesser merklich 
wechselnd. 

“‘Typus-,, Art ““ Th. callianassae mit den Charakteren der ,, Gattung “‘ aus dem 
Burdigal von Burgschleinitz bei Eggenberg. N : D. Typusexemplar das im Palaon- 


132 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


tolog. u. Palaobiolog. Institut der Universitat Wien verwahrte Ursttick zu Ehrenberg 
1938 Tafel 28,5.” 

A brief diagnosis in English has been given by Hantzschel (1962). On the basis 
of the present material it may be emended as follows: 

Extensive burrow systems with both vertical and horizontal elements. Burrows 
cylindrical, between 2 and 20 cm. in diameter. Branching regular, characterized by 
Y-shaped bifurcations, swollen at point of branching. Horizontal elements joining 
to form polygons. Burrow dimensions variable within a system. Horizontal 
systems connecting to surface by vertical or steeply inclined shafts, widely associated 
with callianassid remains. 

Hantzschel (1962, 1965) regards Vomacispongites de Laubenfels (1955 : 108) as a 
synonym of Thalassinoides. Vomacispongites was introduced by de Laubenfels as an 
“ unrecognizable supposed sponge ’’, as follows: 

“ Vomacispongites de Laub. nom. nov. (pro Spongites Schloth. 1820 (non. Oken 
1814))”’, the type species is Spongites pertusus Schlotheim (1820 : 369) based on a 
specimen from a Cretaceous chert from Amberg (W. Germany), compared by von 
Schlotheim to Spongia pertusa Esper (Esper 1799 : 246-7, pl. 26, figs. 1,2). Esper’s 
figure is clearly a sponge, and I can only presume that Hantzschel has examined the 
original specimen, since the original description does not suggest a Thalassinovdes. 
The genus Aschemomia Dettmer (1914) is too poorly defined for comparison, but may 
well be a Thalassinoides. 

In addition to the association of Thalassinoides with Callianassa sp. recorded by 
Ehrenberg (1938), Glaessner (1947) describes what are clearly Thalassinoides in 
association with callianassids from the Eocene of Victoria (Australia), whilst Mertin 
(1941) records Protocallianassa in association with what are probably Thalassinoides 
in the Upper Cretaceous of Germany. Hantzschel (1965), Seilacher (1955, 1964), 
Farrow (1966) and Hallam (1961) all regard Thalassinoides as a crustacean burrow. 

Thalassinoides is very widespread, and has been recorded from the Trias (Reis 
1910, Fiege 1944), Lias (Rieth 1932, Seilacher 1955, Hallam 1961), Oxfordian (Wilson 
1949), Portlandian (Pruvost & Pringle 1924, Arkell 1935), Cretaceous (Geinitz 1842 
etc.) and Tertiary (Ehrenberg 1938, Glaessner 1947). The geographical range of 
this form covers Europe, Asia and Australia. 

In Britain, this trace fossil has been recorded from the Lower Lias by Hallam (1961), 
whilst the fucoids recorded by Blake & Hudleston (1877 : 271) and Arkell (1936 : 63) 
from the Oxfordian (Corallian, Nothe Grits) of the Dorset coast, andfigured from a similar 
horizon in Yorkshire by Wilson (1949 : 256, pl. 10) are clearly Thalassinoides, as 
are the fucoids figured by Arkell (1925 : pl. 22, a) from the Portlandian (Portland 
Sand, Black Sandstones) of the Dorset coast. Farrow (1966) records it from many 
levels in the Yorkshire Jurassic. 

I have noted this trace fossil at many horizons and localities: Triassic: Rhaetic, 
South-Devon coast between Seaton and Lyme Regis, piping the basal bone bed into 
the underlying Keuper (Text-fig. 2, G.). Jurassic: The whole of the Dorset Lias 
(Text-figs. 1, G-J; 2, F). Cretaceous: Lower Greensand, Folkestone beds at Folke- 
stone (Text-fig. 2, I-K) associated with Gyrolithes type structures; Upper Greensand 
of Southern England and throughout the whole of the Lower Chalk and in the Middle 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 133 


se (Ee 


Sa 


Fic. 1. A. Thalassinoides sp. Lower Chalk, ?Upper Cenomanian; White Nothe, 
Dorset. Plan, x7. B, c. Thalassinoides saxonicus (Geinitz). Lower Chalk, Middle 
Cenomanian, Chalk below Totternhoe Stone; Houghton Regis, near Dunstable, Beds. 
Plan, x35. D, F. Laminated structures. Lower Chalk, Middle Cenomanian; near 
Beachy Head, Eastbourne, Sussex, Plan, x7. rE. Laminated structure. Lower 
Chalk, Middle Cenomanian, bed 7; Folkestone, Kent. Plan, x7. Gj. Thalas- 
sinoides sp. Upper Lias, Toarcian; near Seatown, Dorset. Plan, x7. x. Thalas- 
sinoides sp. Upper Greensand; Foxmould, Humble Point, South Deyon, Plan, x +. 


134 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


and Upper Chalk where burrows are preserved (i.e. the Melbourn Rock (Lower 
Turonian) and below the Chalk Rock (Upper Turonian)). At least four forms can be 
recognized in the Lower Chalk. 


Thalassinoides saxonicus (Geinitz) 
(Ceding sikex et elec cies Se ell, Oy les, Bo ANS” Weqeiies, 3c, 15, C3 A, iB) 


1842 Spongites saxonicus Geinitz:96, pl. 12, fig. 1 only (fig. 2 = Ophiomorpha nodosa 
Lundgren). 


1852 Spongites saxonicus Geinitz; von Otto : 20, pl. 6, figs. 2, 3. 

1871 Spongites saxonicus Geinitz; Geinitz : 21, pl. I, figs. 1-5 only. 

1878 Spongia saxonica Geinitz; Fri€ : 149. 

1878 Spongites gigas Fri€: 75, 149. 

1885 Spongites saxonicus Geinitz; Poéta : 30. 

1899 Spongites saxonicus Geinitz; Semenow : 6. 

1909 Cylindrites spongioides Goeppert emend. Richter : 8, 11. 

1912 Spongites saxonicus Geinitz; Dettmer : 114-126 (pars.), ?pl. 8, figs. 4-6. 
?1914 Aschemonia gigantea Dettmer : 287, fig. 

1915 Spongites savonicus Geinitz; Dettmer : 285-287 (pars.). 
?1928 Spongites sp. Lamprecht : 8, 9, pl. 2. 

1932 Spongites saxonicus Geinitz; Rieth : 30, pl. 5a, 1, 2. 

1934 Spongites saxonicus Geinitz; Andert : 68. 

1934 Spongites savonicus Geinitz; Hantzschel : 313. 

1944 Spongites saxonicus Geinitz; Fiege : 419. 

1952 Spongites saxonicus Geinitz; Hantzschel : 146. 

1954 Cylindrites saxonicus Prescher : 50, text-fig. 19. 
21955 Spongites sp., Seilacher : text-fig. 5, 98. 

1962 Spongites saxonicus Geinitz; Hantzschel : 218. 

1965 Spongites saxonicus Geinitz; Hantzschel : 88. 

1967 “‘ Spongites’”’ saxonicus Geinitz; Kennedy : 368 

DiaGnosis. Thalassinoides with horizontal tunnels between 5 and 20 cm. in 

horizontal diameter. System very extensive, tunnels joining to form huge polygons 
up to 60 cm. across, connected to surface by short vertical shafts. Surface of burrow 
mamillated, individual mounds 5 to ro mm. long, elongated parallel to length of 
tunnel. 


LECTOTYPE. Here designated, the original of Spongites saxonicus Geinitz 1842, 
pl. 22, fig. r only: Upper Cretaceous; Germany. 


DESCRIPTION. Systems arise from short, vertical shafts, equal in diameter to the 
widest part of the horizontal elements, which are up to 40 cm. below the surface. 
The horizontal tunnels are elliptical in section and at a single level. Tunnel diameters 


Fic. 2. Aa—p. Thalassinoides visurgiae Fiege (after Fiege 1944) xX}. E. Spongites 
saxonicus Geinitz, Sketch of lectotype (after Geinitz 1842) x}. ¥F. Thalassinoides sp. 
Lower Lias; Pinhay Bay, S. Devon. Plan, x7. G. Thalassinoides sp. Top of 
Keuper, full of Rhaetic Bone Bed; Charlton Bay, S. Devon. Plan, x}. Hu. Thalas- 
stnoides sp. Upper Chalk, Upper Turonian, Chalk Rock; Hitch Wood, near Hitchin, 
Herts. Plan view of 3-dimensional tunnel system beneath the Chalk Rock hardground. 
x4. I-K. Thalassinoides sp. Lower Greensand, Folkestone Beds, Lower Albian; 
Copt Point, Folkestone, Kent. Plan, x 3. 


136 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


vary between 20 by 13 cm. in the centre of systems, to 5 by 3:5 cm. at the extremities. 
Branching is very regular, at intervals of about 30 cm. tunnels bifurcate, with a 
symmetrical Y-shaped junction, slight widening giving rounded angles. The overall 
pattern is of large polygons up to 60 cm. across (Plate I, fig. 1). Specimens showing 
terminations are uncommon; the ending figured (Plate 5, fig. 2) is swollen, measuring 
12 by 5 by 3:5.cm. at the end of a 3 by 2-5 cm. tunnel. The outer surfaces of tunnels 
are covered by low mounds: onsmall specimens these vary from 17:5 to 18 mm. long 
by 7-5 to 11-5 mm. wide by 3:5 to 6-5 mm. high: on larger specimens 16-18 mm. by 
g-I2 mm. by 4-6 mm. The arrangement of these mounds shows little regularity 
other than a preferred orientation parallel to the length of the tunnel. These 
structures are rarely preserved on bottom surfaces, which are covered by a felted mass 
of Chondrites burrows (PI. 5, fig. 3). 

Sections of tunnels suggest that some of these mounds are discrete, with a definite 
separation from the burrow filling. The majority have only a suggestion of a plane 
of separation. In addition to mounds, oval depressions of a similar size, surrounded 
by a raised rim are present, as are ridges, generally 20 mm. long and 2 mm. high, 
running between the mounds. 


Discussion. The lectotype, as figured by Geinitz, is a large, branching cylindrical 
body with a maximum diameter of 5 cm. The surface is covered by small mounds, 
5 mm. long and 2 to 3 mm. wide, elongated parallel to the length of the branches. 
A smooth half cylinder 5 mm. in diameter runs along the centre of the main part, 
joining with similar bodies on the branches (Text-fig. 2, E). The other specimen 
figured by Geinitz (pl. 22, fig. 2) can clearly be referred to Ophiomorpha nodosa 
Lundgren. 

Geinitz regarded Spongites saxonicus as a horny sponge (Ceratospongidae), a view 
also held by von Otto (1854), Fri¢ (1878), Pocta (1885) and many other early workers. 
Goeppert (1842 : 115, pl. 46, figs. 1-5, pl. 48, figs. 1, 2) described what he regarded as 
a fossil alga, Cylindrites spongioides, and he subsequently (1847) considered this 
species to have priority over S. saxonicus, and that both were algae. Cylindrites 
spongioides, as originally proposed, includes a number of different trace-fossils. 
Forms figured on plate 46, figs. I-4 are simple crustacean burrows (type B, p. 47), 
or possibly Ophiomorpha. The other specimens (pl. 46, fig. 4; pl. 48, figs. 1, 2) are 
smooth cylindrical burrows with swollen portions, differmg from S. saxonicus in 
smaller size and lack of ornament. 

Cylindrites has been used by many authors for fucoids (Eichwald 1865, Watelet 
1866 etc.) or trace fossils (Prescher 1954), but is not available due to prior usage by 
Gmelin (1793) and Sowerby (1825) as gastropod genera. Richter’s (1909) emendation 
of Cylindrites is unfortunate, for he clearly includes large burrows (up to I5 cm. in 
diameter), probably Thalassinoides saxonicus, specimens of Ophiomorpha nodosa 
(pl. 9) fig. 7, pli 12, fig.5) pl. 13) ' ties 6), plant debrsi (pl; 12) fies! i. 2 please so) 
and smooth burrows with swollen portions (pl. 9, figs. 1-2). 

As pointed out by Hantzschel (1952), Cylindrites sbongioides may be a synonym of 
Halymemites cylindricus Sternberg: 

“H, fronde fistulosa terente pinnatim ramosa, ramus opposites simplicibus 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 137 


patenibus cylindricus obtusis, terminale longiors . . . In schisto saxi arenaci Pirnensis 
(Greensand anglorum) prope Tetschen ad albim Bohemae.”’ (Sternberg 1833.) 

Until the branching pattern of C. spongioides is described, it is not possible to 
decide if it is a form of Thalassinoides, although it is clear that it is a smooth crusta- 
cean burrow, the swollen portions representing “‘ turn-arounds ’’, comparable to the 
burrows produced by the living crustaceans Upobegia pugettensis (Dana) (MacGinitie 
1930) and Callianassa californiensis Dana (MacGinitie 1934, Stevens 1928). These 
burrows were noted as early as 1760 by Schulze (41-46, pl. 2, figs. 1-5) who regarded 
them as crinoid remains. In view of their interpretation as callianassid burrows it is 
interesting to note that Goeppert (1854) recorded C. spongioides in association with 
remains of Protocallianassa antiquua (von Otto). 

Dettmer (1912) regarded Spongites saxonicus as a giant foraminiferan! 

Hantzschel (1934, 1935) records Xenohelix saxonica Hantzschel (=Gyrolithes 
Saporta) associated with Spongites saxonicus; spiral structures, perhaps Gyrolithes 
occur in the Folkestone beds (L. Albian) at Folkestone, Kent in association with 
Thalassinoides, and have been recorded associated with Ophiomorpha in the Miocene 
of Borneo (Keij 1965) and elsewhere (Kilpper 1962). This type of association indicates 
the artificial nature of trace-fossil taxa, as it suggests that Gyrolithes, Thalassinoides 
and Ophiomorpha are all synonymous, the first having priority. 

The best preserved examples of 7. saxonicus I have found are from beneath the 
Totternhoe Stone (Middle Cenomanian) of the Chilterns, particularly Houghton 
Regis (Bedfordshire). Here, hard, gritty Totternhoe Stone is piped into the very 
soft chalk below and the burrows so filled can be completely freed of matrix (Pl. 5, 
mec. 3 Pil 6; figs. 3,4). 

The presence of phosphatic pebbles and shells in these burrows indicates that they 
were open on the sea floor, and were filled passively, probably after being vacated. 
Individual systems extend over several square metres and indicate firm sediment, as 
I have never seen signs of collapse into them. 

The ridges on the outer surface are interpreted as scratches produced by the 
inhabitant whilst digging or moving through the system; the mamillated surface as 
a result of worked pellets pushed into the wall of the tunnel and smoothed off or 
worn smooth by the passage of the animal’s body. Pellets are impressed into burrow 
walls in this manner by the crustacean Callianassa major Say (MacGinitie im Hantz- 
schel 1952, Weimer & Hoyt 1964). The oval depressions with their surrounding 
ridges appear to be the sites of pellets of soft chalk which have been washed away in 
preparation. The most likely purpose of these pellets is to support the burrow walls, 
a procedure used by living callianassids (Pohl 1946); swollen portions at points of 
branching and burrow terminations are comparable with the “ turn arounds’”’ of 
burrows of this group (MacGinitie 1930, 1934, Pohl 1946). All the features of 
T. saxomicus are thus comparable with Recent callianassid burrows. This view is 
enhanced by the presence, in the infilling of T. saxonicus, of rod-like phosphatized 
faecal pellets (type A of Wilcox 1953), more abundant than elsewhere in the Lower 
Chalk, which, from the presence of internal canals, are diagnostic of anomurans 
(Wilcox 1953, Moore 1932). 

Internally, these burrows show intense re-working (see p. 149). A puzzling feature 


138 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


of previously described specimens of T. saxonicus is the small burrow running down 
the centre of the lower surface of the system. In the lectotype this is very regular, 
but in other specimens it clearly strays from the mid-line. Geinitz (1842) interpreted 
this as a juvenile sponge. My own material suggests that this is another, smaller 
species of Thalassinoides, which sometimes follows the mid-line of the bottom of 
the larger burrow, but which often leaves, passing out into the surrounding sediment 
(Pl. 6, fig. 4). These smaller burrows may be the products of the juveniles of the 
T. saxonicus animal, but as I have never seen transitions it is regarded as a distinct 
form, T. ornatus noy. (p. 141). 

Whilst most systems correspond to the above description, occasionally tunnels 
are found filled with coarse, sandy chalk made up of shell fragments and microfossils. 
This material represents the remains of the burrow filling after the inhabitant has 


a 


B C 
Fic. 3. Alternative interpretations of laminated structures. a. As surface trace; B. 
As partially filled burrow; c. As totally filled burrow with semi-circular section. 
All x4. 


sifted out the finer portion for ingestion; the faecal pellets associated with these 
burrows show only fine-grained material when sectioned (Wilcox 1953), suggesting 
this mode of feeding. Presumably the coarser debris was normally removed from 
the system and washed away by bottom currents, being only occasionally packed into 
a disused part of the burrow. In a single instance, from the Upper Cenomanian at 
Dover, a large mass of this coarse debris, lying above a T. saxonicus system seemed 
to represent material dumped outside the burrow opening adjoining the entrance 
shaft. 

Thalassinoides saxonicus and “ Laminated structures’”’. I have used the name 
“laminated structures”’ (Kennedy 1967) for problematic structures occurring 
throughout the Lower Chalk which, in section, show fine, horizontal laminations 
made prominent by their resistance to weathering (due to a calcite cement) and brown 
colour (due to disseminated limonite). In plan, these structures show a form identical 
in size-range and mode of branching with T. saxonicus (Text-fig. I, D-F). In section 
they can be described in terms of a continuous series defined by two end members: 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 139 


(i) Horizontal bands, up to 60 cm. long and 5—10 cm. deep, laminated throughout, 
the laminations essentially parallel. 

(ii) Semi-circular sections, the curved surface downwards, with diameters from 
Io cm. upwards. With increasing diameter the radius of curvature of the lower 
surface increases, passing into form (i). Laminations are essentially parallel, 
with a tendency to dip towards the centre of the section. 

In both cases, weathered and cut sections show that the laminations consist of 
alternations of normal chalk and coarse debris of shell and echinoderm fragments, 
foraminifera and other sand grade microfossils, cemented by calcite and coloured 
brown by small quantities of limonite, perhaps after pyrite. The laminations are 
between 2 and 20 mm. thick, and may vary laterally (Pl. 8, fig. 3). In thin section, 
these structures show very ill-defined graded bedding, the coarse material grading up 
into the normal chalk above. 

These laminated structures are cut by burrows (PI. 8, fig. 3; Pl. 5, fig. 1) indicating 
a primary origin. Whilst the general sense of the laminations is horizontal and paral- 
lel, corrugations and other disturbances are common (PI. 8, fig. 3). Some of these 
structures are clearly the result of subsequent burrowing (PI. 8, fig. 3), whilst other 
irregularities appear to be the result of slumping of the layers (PI. 8, fig. 3). Bottom 
surfaces are rather irregular (PI. 8, fig. 3), in part as a result of burrows along the basal 
interface. 


INTERPRETATION. In view of the similarity in size-range of these structures and 
Thalassinoides saxonicus and the identical branching pattern, they are clearly the 
result of the activities of the same organisms; crustaceans. Whereas T. saxonicus 
is clearly a burrow, elliptical in section, laminated structures generally have a flat 
top. Three interpretations are possible (Text-fig. 3). 


(i) They are the filling of the lower parts of burrows. 
(ii) They are completely filled burrows semi-circular in section. 
(11) They are a surface trace. 


I have examined many examples in the field; most show no indications of an 
associated burrow. A few show what could be interpreted as the upper part of a 
burrow, but at present the evidence suggests they were a surface trace, although the 
relationship seen in Plate 8 could be interpreted as the intersection of two burrows 
with a semicircular section, completely full of laminated sediment. 

The laminations are interpreted as the result of sifting of the sediment by the ani- 
mals producing these structures. As already indicated (p. 137) faecal material suggests 
they lived on the finer fractions; the coarse layers are the remains left after this 
sifting. Whilst this can explain the formation of one layer, I can offer no explanation 
of the repeated alternation of coarse and fine layers. 

Explanation of these structures as a feeding trace of Teichichnus type (Seilacher 
1955, Hantzschel 1962) is unsatisfactory due to the absence of an obvious burrow in 
association, unless the initial burrow were very shallow and invariably broke the 
sediment-water interface. An inorganic origin—that these are Thalassinovdes, 
exposed by erosion and filled by swept-in coarse material alternating with fine mud 
deposited by gravitational settling or other currents—is rejected; other hollows on the 


140 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


sea floor lack a laminated fill, whilst one would expect to find truncated Thalassinoides 
without a laminated fill, which I have never seen. 


OcCURRENCE. Solid specimens of 7. saxonicus occur abundantly beneath the 
Totternhoe Stone in the Chilterns. Large Thalassinotdes, identical in size and mode 
of branching are common in all coastal sections whilst large oval burrow sections are 
abundant in all sections and are regarded as identical with T. saxomicus. A large 
species of Thalassinoides occurs beneath the Chalk Rock (Text-fig. 2, H) but differs 
from T. saxonicus in having three-dimensional tunnels. These were described by 
Billinghurst (1927) as “ solution channels ”’ 

T. saxonicus is widely recorded from the Cretaceous of Germany and Central 
Europe. The specimen of Thalassinoides figured by Seilacher (1955) from the 
Tertiary may belong to this form. ‘“‘ Laminated structures ’’ are common through- 
out the whole of the Lower Chalk, particularly in the Middle Cenomanian. At 
Folkestone (Kent) bed 7 (Jukes-Browne & Hill 1903) can be traced all along the 
coast, even when high in the cliffs, because of the abundance of these structures. 


Thalassinoides cf. suevicus (Rieth) 
(Bias tig 2) 


1932 Spongites suevicus quenstedti Rieth : 274. 
1932 Spongites suevicus Quenstedt; Rieth : 292. 
1932 Cylindrites suevicus (Quenstedt) Rieth, pl. 134, b. 
?1944 Thalassinoides visurgiae Fiege : 416-421, 424, text-fig. 4. 
1955 Spongites suevicus Quenstedt; Seilacher, text-figs. 5, 57. 
?1964 Thalassinoides sp. Hantzschel : 302, pl. 14, fig. 3. 
1964 Thalassinoides suevicus (Rieth); Hantzschel : 302. 


A Thalassinoides with tunnel diameters between 2 and 5 cm. is occasionally seen in 
allen blocks of Upper Greensand and Lower Chalk at many coastal sections (East- 
bourne, Compton Bay, etc.). Those in the Upper Greensand in part arise from the 
base of the Glauconitic Marl. 

In size, mode and angle of branching these are comparable with “ Spongzites ”’ 
suevicus Rieth, from the Lias and Dogger of Germany (as pointed out by Hantzschel 
(1964 : 302) this name must be attributed to Rieth). There is also a strong resem- 
blance to the fragment figured by Hantzschel (1964) from the Campanian of Beckum 
(Westphalia). 

Thalassinoides visurgiae Fiege, from the Trias (Muschelkalk) of North Germany, 
is based on branching portions (Text-fig. 2, A-D) and appears identical with T. 
suevicus. 

T. cf. suevicus differs from T. saxonicus in its much smaller size and absence of 
ornamentation. It is not referred definitely to T. swevicus because of the poor 
preservation. The systems are horizontal as far as has been seen. It is not clear 
how much of the piping beneath the Glauconitic Marlis due to this form (PI. 1, fig. 3), 
but attitude and tunnel diameters are comparable. 

Specimens of Thalassinoides from the Upper Greensand and from beneath the 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 141 


Totternhoe Stone at Hunstanton, agreeing in size with this form occasionally show 
internal structure, seen in section as concavo-convex laminations (Text-fig. 6, D). 
This type of burrow filling is discussed on page I6T. 


OccURRENCE. Fairly frequent in the whole of the Lower Chalk of southern Eng- 
land. Comparable forms occur in the Lias and Upper Greensand: Lias and Dogger 
of Germany and Campanian of Bochum, Germany. 


Thalassinoides ornatus ichnosp. noy. 
(PING stie 4 SEG, en) 


Diacnosis. Small Thalassinoides, tunnel diameters between 16 by 8 mm. and 
22 by 10 mm. System largely horizontal, surface of tunnels covered in reticulate 
ridges. 

HoLotyrPe. B.M. (N.H.) T.559. Paratype B.M. (N.H.) T.55r. 


LocALITY AND HORIZON. The holotype (associated with T. saxonicus) is from the 
Lower Chalk immediately beneath the Totternhoe Stone at Houghton Regis (Bedford 
shire) (National Grid Reference T.L.013233) and is Middle Cenomanian in age. The 
paratype is from the same horizon and locality. This species is not uncommon 
beneath the Totternhoe Stone elsewhere in the Chilterns: poorly preserved material 
from the Lower Chalk of the Weald may also belong to this form. 


DEscrRiPTION. The tunnels are generally horizontal or gently inclined, with 
typical Thalassinoides branching pattern. Individual tunnels are oval in section, 
dimensions varying between 16 by 8 mm. to 22 by 10 mm. The whole surface is 
covered in delicate intersecting ridges (PI. 7, fig. 6); some tunnels are gently curved. 
Branching points are swollen, whilst swollen portions with diameters of about three 
times that of the adjoining tunnel are present. 


Discussion. This form is quite common beneath the Totternhoe Stone in Bed- 
fordshire, often following the mid-line of the lower surface of T. saxonicus burrows 
(Pl. 6, fig. 3). As already suggested (p. 138) this may be the explanation of the cylin- 
drical central body figured by previous workers (Geinitz 1842, 1871, von Otto 1854, 
Seilacher 1955 etc.). This pattern is not regular, the smaller burrows often passing 
through the larger burrows and occurring in the surrounding sediment. 

Interpretation of T. orvnatus as the work of juveniles of T. saxonicus is considered 
unlikely in the absence of intermediate forms. 

As with the forms of Thalassinoides already discussed, the features of T. ornatus 
agree with an interpretation as crustacean burrows: reticulate surface ridges are 
scratches on the inside of the burrow produced during digging or when moving through 
the system, the swollen portions are clearly “ turn-arounds ”’ 

The surface ornament of T. ornatus resembles that on Spongeliomorpha (p. 151), 
also regarded as a crustacean burrow. The two forms are distinguished by the more 
regular ornamentation and branching of T. ornatus. This form differs from T. cf. 
suevicus by the presence of a reticulate ornamentation and swollen “ turn- 
arounds’”’. Clearly, with poorly preserved material the two forms may be confused. 

GEOL. 15,3. 15 


142 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 
Thalassinoides paradoxica (Woodward) 
(Ple3; Plas PleS, ne. 56 Pil optics 25) Next ttesn45)5 7A —B) 


1814 .. .singular organic body . . ., Webster, pl. 27, fig. 1. 

1823 .. . a remarkable ramifying zoophyte. . ., Taylor : 82. 

1830 Spongia pavadoxica Woodward : 5. 

1833 Spongia pavadoxica Woodward; Woodward : 29, 30, 54. 

1835 ...aramose zoophyte. . . Rose : 54, 275, 270. 

1859 Spongia pavadoxica Woodward; Wiltshire : 275, 277, pl. 1, figs. 1, 2. 
1864 Spongia paradoxica Woodward; Seeley : 331. 

1869 Siphonia parvadoxica (Woodward) Wiltshire : 176. 

1871 Problematicum, Geinitz, pl. 38, fig. 8. 

1884 Spongia paradoxica Woodward; Hughes : 273-279. 

1899 Spongia pavadoxica Woodward; Whitaker & Jukes-Browne : 36, 55. 
1900 Spongia paradoxica Woodward; Jukes-Browne & Hill : 303. 

1903 . . . Stems of Stphomia. . . , Julkes-Browne & Hill : 209. 

1932 Problematicum, Rieth, text-fig. 35 (after Geinitz). 

1961 “‘ Spongia pavadoxica’’ Woodward; Peake & Hancock : 301, 330. 
?1961 ‘‘ Spongia pavadoxica’’ Woodward; Rios & Hancock, pl. 16. 

1962 Spongia pavadoxica Woodward; Hantzschel : W 242. 


DiaGnosis. Medium sized Thalassinoides, with irregular, very extensive horizon- 
tal burrow network, occurring at several levels, connected by vertical shafts. 
Diameter of tunnels variable, between 7 and 60 mm., short blind tunnels very com- 
mon. Surface covered with longitudinal ridges. Generally occurs associated with 
erosion surfaces. 


NeEotypPe. Here designated, B.M. (N.H.) T.545 from the Paradoxica bed, base of 
Lower Chalk (Lower Cenomanian); Hunstanton Cliff, Hunstanton, Norfolk. 


DEscRIPTION. This is the most irregularly branching Thalassinoides I have seen. 
The burrows have an irregular section, and may be depressed or rounded-angular, 
varying in a single system between 7 and 60 mm. in diameter. A large tunnel may 
give rise to a side branch less than a quarter of its own diameter. As in other species 
of Thalassinoides, the principal element of branching is a Y fork, with an increase 
in diameter around the point of branching, the tunnel tending to widen between the 
forks of the Y. Distance between branching points is very variable, between 1 and 
20cm. Many of the branches terminate after short distances, giving the system an 
antler-like appearance, whilst at every point on the system there are small blunt 
protuberances varying from a few millimeters to several centimetres long, repre- 
senting abandoned or unfinished tunnels. Even smaller knobs are also present. 
Where several branches occur close together the tunnels may widen to form a flat 
chamber (PI. 8, fig. 5) up to 10 cm. long and 5 cm. wide with five or six tunnels leading 
off. 

The most striking feature of the branching pattern is that the Y-forks occur in 
three dimensions, whilst most of the elements of the system are horizontal, joining 
into small irregular polygons (Text-figs. 4, 5, A-B). An individual system can exist 
at several levels, connected by short vertical shafts. At Hunstanton, these levels 
are 5-6 cm. apart, running along the minor erosion surfaces within the Paradoxica 
bed, although elsewhere levels are up to 30 cm. apart (Text-fig. 4, A). The systems 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 143 


- a 


YA 


Fic. 4. Thalassinoides paradoxica (Woodward). A. Junction between Wilmington Sands 
and the overlying Middle Chalk; White a Sandpit, Wilmington, S. Devon. Vertical 
Section, x+. 3B. Lower Chalk, Lower Cenomanian, Paradoxica bed; Hunstanton, 
Norfolk. Plan, x 4. 


are connected to the surface by vertical or steeply inclined shafts 15-30 cm. long. 
On vertical faces, burrow densities are up to 20/1000 cm.” 

As pointed out by Hughes (1884) the surfaces of burrows have a green flakey coat; 
this appears to be glauconite. When cleaned, the surfaces of burrows are seen to be 
covered with rather poorly defined longitudinal ridges (PI. 9, fig. 2). 


144 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


Discussion. The name Spongia paradoxica was introduced by Woodward in 
1830 in a “‘ Synoptic table of British Organic remains’”’. In illustration, he referred 
to a figure in a paper by Webster (1814) ““ On some new variety of fossil Alcyonia ”’, 
recording it from Hunstanton and Southbourne. Subsequently (1833) Woodward 
recorded this form from the Red Chalk and Paradoxica bed. The figure referred to 
(Webster 1814, pl. 27, fig. I) is in illustration of (p. 377) “an account of the singular 
organic body which I observed in the green sandstone stratum under the chalk ”’ 
of the Isle of Wight. The figure is of a large block of Upper Greensand from the 
Undercliff along the southern coast of the island, present whereabouts of this specimen 
unknown! Since Woodward records Spongia parvadoxica from both the Red Chalk 
and Paradoxica bed at Hunstanton, other material, available for lectotype designa- 
tion was clearly in Woodward’s possession. His collection (or what remained of it) 
passed to the Norwich Castle Museum in 1836, and was incorporated in the collections. 
Much of the material, including figured specimens, was missing at the turn of the 
century, and although Mr. B. McWilliams of the Museum has searched the collections 
for any specimens of S. pavadoxica from Woodward’s collection, or labelled in his 
hand, none now remains which can be attributed to him. Asa result, I have selected 
a specimen from the Paradoxica bed at Hunstanton as neotype. 

Although first named by Woodward, these bodies were noted in 1823, in what must 
be one of the earliest records of a burrow from the chalk (albeit misidentified). 
Taylor (1823), describing the sequence in the cliffs at Hunstanton, Norfolk, noted as 
follows: 


“No. 4. 14 feet. A stratum of white chalk, more loose than the last, containing 
no fossil shells: yet it is to be distinguished by a remarkable ramifying zoophyte, 
resembling the roots of trees; about an inch thick, branching and intertwining in 
every direction. Some of the fragments are not unlike the horns of a stag.” 


This is the Paradoxica bed. 
Again, later: 


“No. 6. 2 feet. Red Chalk, of a rough disjointed structure, similar except in 
colour to No. 4, and like it, though in a smaller degree, interwoven with the ramifying 
zoophytes before mentioned.” 


The first use of the name farvadoxica was by Woodward (1830: 5): 
“Spongia paradoxica. Geol. Trans. ii. t.27, f.1. Red Chalk. Southbourn; 
Hunstanton.” 


The Southbourne occurrence would appear to be the same as that given by Mantell 
(1833), in a list of “‘ Fossils from the chalk formation ’’, where a spongia from South- 
bourne (Sussex) is noted. Ina footnote stating, “ the inferior bed of marl which is in 
contact with the Firestone at Southbourne is almost entirely composed of zoophytes, 
milleporites, madreaporites etc., so as to form coral reefs’’—presumably the 
Glauconitic Marl. 

The specimens figured and described by Webster (1814) include a number of forms, 
both burrows and fossil sponges. Plates 27 and 29 represent burrows, plate 28, 
figures 3 (in part), 4, 8, 9, 10 and 11 represent the “ tulip alcyonidium ” (Siphonia 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 145 


tulipa Zittel). The nature of the specimens figured as pl. 28, figs. 5-7 is not clear, 
but they resemble Cylindrites spongioides (Goeppert 1842), here regarded as a crus- 
tacean burrow. 


The next reference to ‘“‘ Spongia paradoxica ”’ is by Woodward (1833: 29): 
“ Chalke Marle. This bed reposes upon the red chalk, and is seen to great advantage 
in that interesting section, Hunstanton cliff. It is of a grayish color, and at that place 
about four feet in thickness. The Spongia paradoxica,as we have named it pro 
tempore, abounds init”... 


Again, (p. 30): 
“ The Red Chalk . . . it is about two feet in thickness, and, like its superincumbent 
bed, abounds with Spongia paradoxica.” 


Rose (1835), describing the Red Chalk at Hunstanton speaks of “a ramose zoo- 
phite, the nature of which is not satisfactorily determined’’. Again (p. 275), 
under the heading “‘ Chalk without flints ’’, describes the lowest bed as being ‘‘ made 
up of a ramose zoophyte, which strongly characterizes it ’’, regarding it (p. 276) as 
“ best explained by supposing it originally a coral reef and its interstices filled with 
Cretaceous Mud.” 

Wiltshire (1859: 275), in a list of fossils from the Red Chalk records “‘ Spongia 
paradoxica Geol. Trans. 2, tab. 27, fig. 1. page 377 (In the collections of Mr. Rose 
and Author.)’’. Later (p. 277, footnote): “‘ Siphonia pyriformis 1s probably the 
head of Spongia paradoxica. In the cabinet of Mr. Rose is a mass of the latter, to 
which a head similar to the one figured isattached’’. The figures referred to are the 
first of S. favadoxica from Hunstanton published. Wiltshire’s pl. 1, fig. 1, shows a 
typical branching fragment, fig. 2, referred to as Siphoma pyriformis is a swollen 
cylindrical body, the terminal portion being flat, with a circular depression surrounded 
by a raised rim. 


¢ 


Seeley (1864), refers to “‘ organic growth known as ‘ spongia paradoxica’ in the 
sponge bed and top of the red chalk’. Wiltshire (1869), describing the Hunstanton 
section, notes ““a meandering and many-branched sponge, Szphonia paradoxica”’ 
from his bed b (the Paradoxica bed), whilst “‘ Spongia paradoxica Webster ”’, is 
recorded from the highest band of the Red Chalk. 

By far the most extensive discussion is that of Hughes (1884) who concludes 
(257-277) that Webster’s figure is a different fossil, the “‘ tulip alcyonidium ”’, and 
that the fossil Spongia paradoxica is in fact an inorganic body, as sponge structure is 
preserved in the surrounding rock, but never in S. paradoxica. Large shell fragments 
in the matrix indicate conditions unsuitable for a delicate sponge, fragments of the 
Spongia are never found in the matrix, whilst shell fragments are avoided and 
never encrusted as would be expected in the case of a sponge. 

This inorganic origin is accepted by Whitaker & Jukes-Browne (1899) who repeat 
Hughes’ views, and Jukes-Browne (1900, 1903), who refers to “ curious cylindrical 
bodies ... which resemble the stems of Szphonia but which do not contain any 
sponge structure’’. The most recent account of this “‘ organism ”’ is that of Peake & 
Hancock (1961), describing the Paradoxica bed: 


146 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


Fic. 5. A, B. Thalassinoides pavadoxica (Woodward). A, Lower Chalk, Lower Ceno- 
manian, Paradoxica bed; Hunstanton, Norfolk. Plan, x}. 8, Middle Chalk, Lower 
Turonian, Melbourn Rock; Brockham Limeworks, Betchworth, Surrey. Plan, x. 
c. Thalassinoides sp. Lower Chalk, Middle Cenomanian; cliffs below Whitbred Hole, 
Eastbourne, Sussex. Vertical section showing entrance shaft, x 4. 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 147 


“ soft-bodied organisms have left casts of their burrows which now form radiating, 
cylindrical branching and intertwining masses; they were once thought to be sponges, 
and actually named Spongia paradoxica’’. 

Hantzschel (1962) includes “‘Spongia paradoxica Woodward 1833 (=Siphonia 
paradoxica AUCTT.) ” in a list of unrecognized and unrecognizable genera of trace 
fossils, giving Taylor’s description and Hughes’ views on its inorganic origin. 

I have no doubt that this is a Thalassinoides, from both mode of branching and 
scratches; and that it is a crustacean burrow. The irregular three-dimensional 
branching makes it readily separable from other forms of Thalassinoides. The short 
blind burrows give a superficial resemblance of some parts to Spongeliomorpha. 

Apart from its record in the English literature, already discussed, this type of 
burrow was described as early as 1760 by Schulze, who regarded them as crinoid 
remains. Problematic structures figured by Geinitz (1871) from the German Upper 
Cretaceous are clearly T. parvadoxica. Spongia sudolica Zareczny (1878), regarded by 
Raciborski (1890) as a Spongeliomorpha, resembles T. paradoxica in size, but has 
rather different ornament; it is clearly a Thalassinoides. 

In Britain, T. paradoxica has a very limited distribution, occurring only in associa- 
tion with minor erosion surfaces and signs of early lithification-hardgrounds. At 
Hunstanton the burrows occur associated with the erosion surfaces at the top of the 
Paradoxica bed, the Red Chalk and a minor erosion surface within the Inoceramus 
bed. The burrows in the Paradoxica bed tend to spread out along the minor erosion 
surfaces within the bed, but often pass through them. At the base, they follow the 
undulating irregular surface of the Red Chalk, but never pass into it. Those in the 
overlying Inoceramus bed follow the surface of the Paradoxica bed in like fashion. 
In both cases, the burrows always avoid pebbles, large shell fragments and echinoid 
tests, indicating that the animals could not bore into hard objects. That the erosion 
surfaces at the top of the Red Chalk and Paradoxica bed are never penetrated, like- 
wise indicates that these were lithified when the burrowers were active in the sediment 
above. In the burrows beneath the Chalk Rock, here preserved as empty cavities, 
brachiopods, echinoids and Inoceramus fragments protrude into Thalassinoides 
burrows, the surrounding sediment having been removed, whilst the hard shell 
was left, again indicating inability to deal with hard objects. 

In the south, the top of bed B. in the Wilmington outlier is penetrated by T. 
paradoxica (Text-fig. 4, A), here to a much greater depth, as there is no lower hard- 
ground to limit penetration. The burrows are excavated in sandstone, and are full 
of glauconitic chalk with small phosphates, identical with that in the base of the 
overlying Middle Chalk (equivalent to bed C. of the coastal sections). The walls 
of these burrows have a phosphatic veneer, as does the overlying erosion surface, 
whilst the sediment immediately around the burrows is impregnated with glauconite; 
this suggests that the lithification prior to these processes occurred either whilst the 
burrows were still occupied, or in the period before they were filled by drifted material. 

This same trace-fossil occurs, associated with hardgrounds, at the top of beds A, 
and B of the Cenomanian Limestone on the Devon coast. It is also present, asso- 
ciated with hardgrounds, in the Middle Chalk above, and elsewhere in Southern 
England in the Melbourn Rock, again associated with hardgrounds. In the Lower 


148 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


Chalk, it occurs below a hardground 11 m. below the flenus Marls at Culver Cliff 
(Isle of Wight). 

In every case there is evidence that the burrow was excavated in soft sediment, 
and that the hardening, phosphatization and glauconitization, some or all of which 
occur in the associated hardground, post-date burrowing, but seem to have occurred 
prior to their silting up. 

I have never seen any comparable burrow systems in chalk away from hard- 
grounds, and believe the association to be a valid one. 

The “ tubulures’ of many continental authors, occurring associated with hard- 
grounds, variously interpreted as tree-roots, algae, annelid, terebellid or crustacean 
burrows (Schroeder & Bohm 1909, Ellenberger 1946, 1947, Marliére 1933 etc.), are 
clearly burrows of a similar type. 


OccURRENCE. The distribution and occurrence of T. paradoxica is fully dealt 
with in the discussion above. 


Ichnogenus CHONDRITES Sternberg 1833 


Diacnosis. “ Very plant-like, regularly ramifying tunnel structures which 
neither cross each other nor anastomose; should be interpreted as dwelling burrows 
or feeding burrows; width of tunnels remaining equal within a system, otherwise 
varying from large (i.e. Buthrotrephis) to small (e.g. Chondrites) very common trace 
fossil, usually named fucoid ... surface pattern commonly very regular, effected by 
phobatactis . . . (probably made by marine worms). Cambrian to Tertiary. Cosmo- 
politan’”’ (Hantzschel 1962 : 187-188). 


TYPE SPECIES. Fucoides targioni Brongniart, by the subsequent designation of 
Andrews (1955). 


Discussion. The synonymy of Chondrites is given by Hantzschel (1962). Scott 
Simpson (1957) has discussed this trace fossil at length, reviewing early interpretations 
and concluding that it is the feeding-trace of some worm-like organism. 

The following features have been indicated as diagnostic (Simpson 1957): 


(a) Circular cross-section. 
(b) Constant diameter (in some cases with constrictions at the point of branching). 
(c) Smooth wall. 
(d) Regular branching pattern: 
(i) Branching tends to be pinnate, especially at the periphery of the system, 
when not interfered with by neighbouring systems. 
(ii) Branching is always lateral, never equal. 
(i) A large number of orders of branching may be present. 
(iv) The pattern lacks symmetry other than a radial tendency. 
(e) Attitude, with both vertical and horizontal elements, the latter undergoing 
extensive ramification. 
({) Phobotactic pattern. 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 149 


Chondrites sp. 
(Bl52; digs: 2, 4; Bis, tigers) (Pleo; tigen) 


A small species of Chondrites with tunnel diameters between I and 2 mm. is 
common throughout the whole of the Lower Chalk. 

Many of the small, horizontal or gently inclined burrows present can be referred 
to this genus; every section I have examined contains this form, which is also occa- 
sionally encountered in the Glauconitic Marl. 

Horizontal sections show that the vertical elements of these systems have a circular 
cross section; vertical sections show that the horizontal or gently inclined elements 
have an elliptical section, presumably as a result of compaction (which can be 
demonstrated by the crushing and deformation of associated fossils). Diameters are 
very constant, varying between I and 2 mm. in specimens from many horizons and 
localities. Individual branches and systems show a constant diameter throughout. 
Tunnel walls are smooth, tunnel fills structureless. Tunnels are always straight, 
except at the point of branching. 

Vertical elements are less abundant than horizontal or inclined parts. No example 
of the two joining up has been observed but a sharp change of direction is implied. 
Sections give only limited information about branching but show this to have been 
lateral, never equal and at anacute angle. Horizontal and inclined elements branch 
frequently, vertical elements rarely. 

Burrows never intersect, suggesting a phobotactic behaviour pattern: more posi- 
tive evidence is seen in sections which suggest a “‘ wrapping around ”’ of tunnels, 
embracing on close encounter, then continuing in the original direction. “ Solid” 
specimens—chance fracture surfaces (Pl. 9, fig. 1) or the cleaned surfaces of larger 
burrows from beneath the Totternhoe Stone (Pl. 5, fig. 3) give a better picture of 
the mode of branching. All the features already noted are present. There is no 
obvious symmetry; first and second order branches are present, branching at acute 
angles; pinnate branching is occasionally seen. Phobotactis is expressed in terms of 
“embracing ’”’ and stopping short. From these features, reference to Chondrites is 
clearly justified. 

There are a wide variety of names available for forms of this size and it seems point- 
less to name the present material. 

As noted above, every section contains these burrows: the maximum observed 
density is about 20 sections per square centimetre. A very characteristic occurrence 
of Chondrites is in the filling of larger burrows (PI. 2, fig. 4). In nearly every instance, 
Chondrites is far more abundant in these than in the surrounding sediment; Thalas- 
sinotdes is particularly prone to this re-working. Beneath the Totternhoe Stone at 
Houghton Regis, the filling of 7. saxonicus burrows is completely re-worked and the 
bottom surface of the burrow converted to a felted mass of Chondrites (Pl. 5, fig. 3), 
whereas this form is uncommon at the base of the Totternhoe Stone and penetrates 
only a few centimetres. Chondrites penetrates to a much greater depth in burrow 
fillings than the surrounding sediment; a similar feature has been noted by Seilacher 
(1964 : 302, text-fig. 3, right-hand figure), Chondrites penetrating to a greater depth 


150 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


in the septum of a Corophioides than in the surrounding sediment (Lias y, S. Germany). 
A number of alternative explanations can be offered: 


(i) The filling of the larger burrows is richer in nutrients than the surrounding 
sediment. 
(ii) Re-worked sediment is better oxygenated. 
(iii) Re-worked sediment is softer and thus more readily penetrated. 


Of these alternatives, I would favour (iii) in view of the occurrences beneath the 
Totternhoe Stone where the presence of other burrowers, feeding on sediment, suggests 
it contained nutrients and was suitable for burrowing. 

The abundance of Chondrites on the lower surface of larger burrows suggests that 
there is a geotropic control on the direction of burrowing, and that the sediment 
surrounding the burrows is not penetrated suggests that it was too stiff for the 
Chondrites animal. The surfaces of Gyrvolithes, as figured by Saporta (1884) are 
covered by Chondrites in a similar fashion. An alternative may be that the Chon- 
drites animal was feeding on mucus lining the burrow. 

Ferguson (1965) has suggested that the filling of Chondrites tunnels was by the 
sucking-in of sediment from the surface-opening of the system as soon as the proboscis 
(or whatever part of the animal produced the burrow) was withdrawn from a branch. 
The arguments for this mode of filling are very reasonable, but it should be noted that 
ammonite siphuncles, borings and echinoid stereomes are sometimes sediment filled, 
indicating that passive filling of such structures can occur. 


OCCURRENCE. Chondrites sp. occurs in all sections of Lower Chalk examined. 
Comparable forms occur occasionally in the Glauconitic Marl and are common in the 
plenus Marls. 


Ichnogenus SPONGELIOMORPHA Saporta 1887 


1887 Spongeliomorpha Saporta : 299, pl. 6, figs. 2, 3. 
?1913 ©Rhizocorvallium; Felix : 21 (non Zenker). 

1945 Spongiliomorpha; Darder, plate 8 (errore). 
1955 Spongeliomorpha; de Laubenfels : E 36. 
?1955 Felixtum; de Laubenfels : E 36. 

1962 Spongeliomorpha; Hantzschel : W 216. 
?1965 Felixium; Hantzschel : 35. 

1965 Spongeliomorpha; Hantzschel : 87. 

1965 Spongiliomorpha; Hantzschel : 87. 


DriaGnosis. Medium sized, elongate, cylindrical, branching tunnel system, 


surfaces covered with network of fine ridges, interpreted as scratch marks; probably 
produced by crustaceans. Range: Triassic to Miocene. 

TYPE SPECIES. Spongeliomorpha iberica Saporta 1887 (299, pl. 6, figs. 2, 3) 
from the Miocene of Alcoy, Spain, by monotypy. 

Discussion. Saporta (1887) described what he believed to be a new form of 
keratosid sponge, Spongeliomorpha iberica, based on material from the Miocene of 
Alcoy (Spain), comparing it with Spongelia Nardo (in fact a synonym of Dysidea 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 151 


Johnson: see de Laubenfels 1955: E 536), a form ranging from Eocene to Recent. 
In addition to the type material, Saporta mentions other material from the Calcaire 
Grossier and the United States. The fossil is indicated as resembling the horns of a 
deer, and being associated with Taonurus Saporta (=Rhizocorallium Zenker), a 
“fucoid’’. Meunier (1889) described, without figuring, the material noted from 
the Calcaire Grossier. This new form, Spongeliomorpha saportai Meunier, from the 
“Sables du Beauchamp ’’, above the Calcaire Grossier, differs from S. tberica 
in its more elongate form and tendency to dichotomous branching (the specimen is 
22 cm. long with a diameter of 2 cm.; lateral second and third order branches are 
present). The surface is said to be covered by ridges more regular, parallel and uni- 
form than in S. zberica. Interpretation of Spongeliomorpha as a sponge is supported 
by Reis (1910), who describes Triassic forms, and de Laubenfels (1955) who compares 
it to the Jurrassic form Sfongelites Rothpletz, a genuine sponge. Darder (1945) 
figures “ Spongiliomorpha”’ iberica, again from the Miocene (Burdigalian) of Alcoy, 
but regards it as algal, and a sexual dimorph of Taonurus ultimus (i.e. a Rhizo- 
corallium) | The most satisfactory explanation is that of Reis (1922) who interpreted 
Spongeliomorpha as a burrow system. 

The genus Felixiwm de Laubenfels (1966), proposed to replace Rhizocorallium Felix 
(1913, non Zenker) with R. glaseli Felix (gldseli recte = glaeseli) as type species, 
appears to be a burrow, perhaps a Spongeliomorpha, perhaps a Thalassinoides frag- 
ment or even the “ arm ”’ of a Rhizocorallium. 

Scratched burrows for which the name Spongeliomorpha seems suitable have been 
discussed and figured by Lessertisseur (1955) from the marine Hauterivian of Andon 
(Alpes-Maritimes, France) and Weigelt (1929) from the Jurassic and Cretaceous of 
Germany. Raciborski (1890) regarded Spongia sudolica Zareczny (1878) as a Sponge- 
liomorpha; from the branching pattern it is clearly a Thalassinoides, possibly a 
synonym of T. paradoxica (vide p. 147). 

The figured material of Spongeliomorpha is all in the form of small fragments. 
The original figured specimen agrees closely with some fragments of Thalassinoides 
paradoxica in general form, whilst the ornament of Spongeliomorpha and Thalas- 
sinoides ornatus suggests that when the branching form of Spfongeliomorpha is 
better known the two names may prove synonymous. Sfongeliomorpha is used 
in the present account for scratched burrows which do not show a Thalassinoides-like 
branching. 

The surface ridges of Sfongeliomorpha are regarded as having the same origin as 
those of Thalassinoides—as a result of the inhabitant digging or moving through 
the system. Once more, only two groups of animals seem likely to produce these 
markings, crustaceans and annelids. Since Weigelt (1929) has figured similar 
scratches on Recent crustacean burrows whilst the same ornamentation is present 
on the fossil crustacean burrow Rhizocorallium (Weigelt 1929, Abel 1935, Hantzschel 
1962), a crustacean origin for Spongeliomorpha is clear. Similar ornamentation 
is also seen on the undoubted crustacean burrow Ophiomorpha (personal 
observation based on material from the English Weald Clay (Lower Cretaceous, 
Barremian)). 


152 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


Spongeliomorpha sp. 
(BIZ tice 7) 


Fragments of a Spongeliomorpha are not uncommon in the Lower Chalk at every 
locality examined. By far the best locality is beneath the Totternhoe Stone at 
Houghton Regis. The cross section is elliptical (presumably as a result of com- 
paction), varying between 30 by 18mm. to16by1z2mm. Straight or slightly curved 
fragments are commonest and occur in both vertical and horizontal positions. 
Occasional narrow lateral branches may be present. The surface is covered by small, 
sharp reticulate ridges intersecting at 80 and 100 degrees. No internal structure; 
surface often covered with small Chondrites and other burrows. 

In size and general form these fragments are closely comparable to S. zberica, 
differing in their less continuous ridges intersecting at a higherangle. None of the 
material I have seen shows the antler-like branching of the figured specimens. 


OccURRENCE. Frequent in all sections of the Lower Chalk examined. 


Spongeliomorpha? annulatum ichnosp. nov. 
(PIE afig. 1; Pls; fig. 5; lext-fie: 65) 


DiaGnosis. Cylindrical branching burrows consisting of a marl cylinder 1-2-5 cm. 
in diameter with a glauconitic core 5 mm. in diameter; outer surface covered by 
longitudinal ridges. Occurring in glauconitic sediments. 

Ho.totyre. B.M. (N.H.) T.554 from the Glauconitic Marl (Lower Cenomanian) ; 
section below the Martello Tower No. 3, Folkestone, Kent. 


MATERIAL. In addition to the holotype, I have examined many hundreds of 
specimens from the Glauconitic Marl and Upper Greensand of Southern England. 


LOCALITY AND HORIZON. Abundant in the Glauconitic Marl at all localities 
examined. Occurring also in glauconitic bands above the base of the Chalk and in 
the glauconitic basement bed of the Lower Chalk in the south-west. Very common 
at many localities and horizons in the Upper Greensand. Widespread in glauconitic 
facies of Cretaceous age all over north-west Europe (J. M. Hancock, personal com- 
munication). 


DeEscriIPTION. Largely horizontal, cylindrical in section with diameters between 
1-0 and 2:5 cm. Branching poorly known, apparently alternate and at an acute 
angle (fig. 6, E). Occurring only in glauconitic sediments, the burrow consists of a 
glauconite-free marl cylinder with a central glauconitic core about 5 mm. in diameter. 
The outer surface of the marl cylinder is covered in longitudinal ridges. 


Discussion. For over 150 years geologists in this country have noted the presence 
of “ stem-like ’’ markings in the Glauconitic Marl and other glauconitic Albian and 
Cenomanian sediments. Webster (1814) regarded these structures as alcyonites 
(sponges). Reid (1898), describing the Upper Greensand near Beachy Head, East- 
bourne (Sussex) mentions. . . 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 153 


“curious cylindrical cavities filled with material differing somewhat from the sur- 
rounding matrix. These are perhaps made by some boring animal, though the 
horizontal position and closed ends often suggest rather the disappearance of buried 
sand-eating Holothurians.”’ 

They are perhaps the “‘ irregular spots and veinings of white marl ’’ noted by Jukes- 
Browne & Hill (1903 : 38) from the Glauconitic Marl at Folkestone (Kent), later 
(p. 265) described as being ... “ areas of small size—seen in the hand specimen as 
whitish markings or pipings are filled with fine amorphous calcareous material to the 
exclusion of the larger glauconite grains”’. What are probably the same burrows 
are noted by Thomel (1961) from an Upper Albian greensand from the Alpes—Mari- 
times, France. 

Although extremely abundant in most sections of Glauconitic Marl and Upper 
Greensand (tunnel densities up to 80 per 1,000 cm.?), the branching pattern is poorly 
known. The surface ornamentation of ridges suggests reference to Spongeliomorpha, 
but because of the peculiar internal structure a new generic name may be useful for 
this type of burrow. 


INTERPRETATION. For reasons already stated, the surface ridges of these burrows 
are interpreted as scratch marks produced by crustaceans. The peculiar internal 
structure can be interpreted as a result of the sifting of sediment into clay, silt and 
sand grade materials during feeding, the animal presumably living on small 
organisms in the coarse fraction. 


Ichnogenus PSEUDOBILOBITES Lessertisseur 1955 


1882 Pseudobilobites, Barrois : 175, pl. 5, fig. 5a, b (not intended as a generic name). 
1955 Pseudobilobite, Lessertisseur, text-fig. 25, G. 

1955 Pseudobilobites Barrois; Lessertisseur : 45. 

1965 ,, Pseudobilobites “‘ Barrois; Hantzschel : 75. 


Diacnosis. Medium sized (3-7 cm. long) rounded or oval masses of sand-grade 
microfossils (largely foraminifera) and shell fragments cemented by calcite, generally 
ironstained, due to oxidation of small quantities of pyrite present. Upper surface 
flat or concave, smooth or slightly granulated. Lower surface convex, convoluted, 
covered by groups of short parallel ridges inclined at an angle to the axis of the struc- 
ture. 


TYPE SPECIES. Pseudobilobites jefferiest ichnosp. nov., here designated. Lower 
Chalk, Middle Cenomanian; Pitstone (Bucks). 


” 


Discussion. The term “ pseudobilobite ’’ was first used by Barrois (1882), in a 
discussion of Bilobites (=Cruziana)—testing trails of trilobites, from the Palaeozoic 
of Northern Spain. Clearly intended as a vernacular name, he applied it to small 
oval masses of microfossils, the lower surfaces of which are covered in ridges, from 
the Lower Turonian of Séry in the Ardennes. 

Lessertisseur (1955) uses the term rather ambiguously: in the explanation of his 
figure 25 G (a copy of Barrois 1882, pl. 5, fig. 5a) he uses the name in the vernacular, 
on page 45, the name is italicized, as are the other generic names in Lessertisseur, 


154 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


and Barrois is given as author, together with the reference. Clearly, it is regarded 
as of generic status. As already noted, Barrois regarded Pseudobilobites as a ver- 
nacular name; Lessertisseur’s use as a generic name, with Barrois as author is not 
justified. The genus Pseudobilobites is, therefore, attributed to Lessertisseur 1955. 

The “‘ problematicum”’ of Jefferies (1962, 1963) is clearly a trace fossil of this 
type. Similar forms occur in the Lower Chalk and are described as Pseudobilobites 
yjefferiest ichnosp. nov., here designated type species of Pseudobilobites. 


Pseudobilobites jefferiesi ichnosp. nov. 
(Pl Gy hier 1; PIV 7, ie 3: Rie tien Pinon tessa) 


1961 Pvoblematicum sp., Jefferies, text-fig. 2. 
1961 Problematicum, Jefferies : 620, 623, 624, 644, pl. 77, fig. 5. 
1963 Problematicum sp., Jefferies : 7, 12, 14, 16, 17, text-fig. 2 (pars.). 


Diacnosis. As for Genus. 


Hototyre. B.M. (N.H.) 1.565. Lower Chalk, Middle Cenomanian; Pitstone 
(Bucks.). 


MATERIAL. Paratypes, B.M. (N.H.) T.556, 566, Lower Chalk, Upper Cenomanian, 
to-15 ft. below base of plenus Marls; below Shakespeare Cliff, Dover, Kent. 
Numerous other specimens from the Lower Chalk and plenus Marls (Sedgwick 
Museum, Cambridge, Jefferies collection). 


DESCRIPTION. Small ovoid masses of sand-grade microfossils (foraminifera) and 
shell fragments, cemented by crystalline calcite and stained brown by limonite, 
derived from the decomposition of the small quantities of pyrite present in un- 
weathered specimens. In shape, specimens vary from elongate ovals, half as wide 
as long, to almost circular, ranging in length between 3 and 7 cm., although larger 
specimens probably also occur. The outline is fairly regular, although often broken 
up by subsequent burrowing. Upper surface smooth or slightly granular, flat or 
slightly concave, lower surface convex, convoluted and irregular, covered by groups 
of short, parallel ridges, inclined to the long axis of the structure. 


Discussion. The original specimen figured by Barrois (1882) differs from P. 
jefferiest in having longer more continuous ridges on the (presumed) under-surface. 
The figure is rather indifferent and re-examination of the material may indicate that 
it is the same as the present form. 

These structures were first recorded from the English Chalk by Jefferies (1962, 1963) 
who briefly described and illustrated a “ problematicum ”’ from the top of the Lower 
Chalk and the plenus Marls. Subsequent collecting shows that they are common 
throughout the whole of the Lower Chalk, and also occur in the Melbourn Rock at 
the base of the Middle Chalk. Specimens show great shape variation in both outline, 
thickness and convexity, but form a quite distinctive group of trace fossils. 

In thin section, the constituents are clearly the coarse fraction of the chalk. 
Foraminifera are abundant, ostracods, shell and echinoid debris plus small masses 
of collophane (? faecal pellets) make up the remainder, with a calcitic cement. 
Burrows passing through these structures suggest they were soft when buried, and 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 155 


that they are not of diagenetic origin (Pl. 9, fig. 6). Occasionally, internal lamina- 
tions are present. Pseudobilobites clearly represents a type of activity like that 
which produced what I have called “‘ laminated structures’. The prominent ridges 
on the base I would interpret here, as elsewhere, as scratch marks, indicative of 
crustaceans. Grouping in threes, fours or fives represents either the co-ordinated 
movement of appendages, or movement of a single appendage with several claws. 
From an examination of these structures in situ, they appear to be a surface trace. 
I have never seen a convincing example in a burrow, although the possibility cannot 
be overlooked. 

This type of structure could result from the feeding activities of an animal sifting 
chalk for the fine fraction, ingesting this and leaving the coarse debris behind. The 
lower, scratched surface, represents the extent of foraging, the concave upper surface 
is perhaps an expression of the position of the body during feeding. 


Not all the segregations of coarse debris in the Lower Chalk belong to this form, 
some (including, in part, some of the “‘ problematicum ”’ recorded by Jefferies (1961, 
1963)) represent the partial or total filling of vertical and horizontal cylindrical 
burrows (a typical fragment is represented in Pl. 6, fig. 2). This type of filling 
probably represents the same type of activity. They sometimes occur closely 
associated with “‘ laminated structures ”’ (Pl. 8, fig. 3) and may be the product of 
the same animal, although separate occurrences show that these could be chance 
associations. 

P. jefferiest is widespread and common in the Lower Chalk and plenus Marls, also 


occurring in the Melbourn Rock (Lower Turonian). 


Keckia(?) sp. 
1911 Keckia (?) sp., Bather : 553, pl. 24, fig. 1. 


Bather’s account of this form is excellent, as is his illustration. Having seen no 
other material, I can add nothing to his account. The nature and interpretation of 
Keckia has been discussed by Hantzschel (1938) and by Richter (1947). 


“ Terebella’’ cancellata Bather 
(EEG tgs: 192) 


1897 Terebella lewesiensis (Mantell) Davies; 145-148 (pars.). 
to11 “‘ Tervebella’’ cancellata Bather : 551-553, 550, pl. 24, figs. 3, 4, No. 5. 


Diacnosis. “ Tube from which the (?gelatinous or mucilaginous) wall has dis- 
appeared, leaving on the internal cast an obscure cancellate ornament formed by 
transverse and longitudinal folds; with diameters from about 0-75 to 2 cm. and with 
a possible length of 19 cm. or more” (Bather rgII). 


HototypPe. B.M. (N.H.) 58253, Lower Chalk, Glynde, Sussex, figured here as 
Plate 8, fig. 1. 


156 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


Discussion. Bather’s description of this “ Terebellid ”’ is excellent, but I believe 
his interpretation to be erroneous. “‘ Terebella’”’ cancellata is clearly a burrow; 
material agreeing with the holotype and the holotype itself all appears to represent 
poorly preserved burrows of a type agreeing with what I have called Spongeliomorpha 
sp. The surface depressions described by Bather (rorr) are the result of rather 
poorly preserved intersecting ridges (i.e. scratches). The paratype specimen, 
B.M. (N.H.) 1574 (Pl. 8, fig. 2) clearly belongs to a different form and is described 
below, as burrow type D. 

From a re-examination of the holotype of “ Terebella’’ harefieldensis White 
(White 1923), here figured for the first time, as Plate 7, fig. 2, it is clearly identical 
with crustacean “ burrows ”’ figured by Weigelt (1929), from a similar occurrence in 
Germany. T. harefieldensis is not a true burrow; excavated in hard chalk, below 
the sub-Tertiary erosion surface it is to be regarded as a boring. From its widespread 
distribution (Hester 1965, text-fig. 2) recognition as a crustacean boring may give 
this form value as a palaeogeographic indicator. No generic name appears to be 
available for this type of boring. 


V. OTHER BURROWS 
The forms described above constitute only a part of the trace fossil assemblage of 
the Lower Chalk. Some of the more obvious burrows, too poor for detailed study 
are noted below. 


Burrow Typrrt A 
(Text-fig. 6, B, C) 


DESCRIPTION. Burrow system made up of four vertical cylindrical shafts between 
6 and 12 cm. long, widening downwards, connected by a horizontal tunnel 16-30 cm. 
long. Tunnel diameters about 2 cm. 


Discussion. I have seen only two complete systems of this type. The systems 
originate at the bases of marls, piping down into the limestones below. The nature 
of the openings is not clear, but the vertical shafts increase in diameter away from 
the surface and are at their widest just above the junction with the horizontal tunnel. 
The spacing of shafts is identical in both examples I have seen: one shaft lies at each 
end, the other two are equidistant from each other, but one is separated from the end 
by nearly twice the distance separating the two inner shafts. 

I have seen no descriptions or figures agreeing with these systems, and in view of 
the identical form of the two examples, I am inclined to regard this as a new form. 

The most similar described system is that of Pholeus abomasifornus Fiege (Fiege 
1944, Hantzschel 1962, 1965) from the Trias (Muschelkalk) of North Germany. 
Pholeus differs from the present form in the absence of intermediate shafts and the 
presence of a swollen horizontal chamber. Pholeus is regarded as a decapod crusta- 
cean burrow. The burrow of the living crustacean Cambarus carolinus Erichsen 
(Fiege 1944, fig. 3) is again similar but a swollen portion (“living chamber ’’) is 
present. 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


D 


Fic. 6. A, Burrow type B, Top of Wilmington Sands, filled by the overlying Middle Chalk; 
White Hart Sandpit, Wilmington, S. Devon. Vertical section, x}. 8, c, Burrow type 


A, Lower Chalk, Middle Cenomanian. B, Folkestone, Kent, c, Eastbourne, Sussex. 


Both 


vertical sections, x4. Db, Thalassinoides sp. Lower Chalk, Middle Cenomanian; 
Hunstanton, Norfolk. Plan, showing septate internal filling. 1. E, Spongeliomorpha? 


annulatum ichnosp. noy. Upper Greensand; Cow Gap, Eastbourne, Sussex. 
GEOL. I5, 3. 


Plan, x 4. 


16 


Woy 


158 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


There is a superficial similarity to the tube system of the living polychaete Lanice 
(Seilacher 1951, Schaefer 1962) but the Chalk form lacks a lining. 

This system cannot be compared with the simple U-shaped burrow of worms such 
as Urechis (MacGinitie 1928) or fossil representatives such as Arenicolites, as the pre- 
sence of four openings would render the functional purpose of the burrow, in terms 
of maintenance of respiratory and feeding currents, too complex. 

There is insufficient evidence to suggest the nature of the inhabitants of this type 
of system. 


OccURRENCE. The two perfect specimens are from the Middle Cenomanian of 
Folkestone and Eastbourne. 


Burrow Tyre B 
(Text-fig. 6a) 


DESCRIPTION. Vertical, cylindrical burrows up to 5 cm. in diameter and 100 cm. 
long. Bottom swollen into an elongate chamber. 


Discussion. Large simple burrows of this type are not uncommon in the upper 
part of the sandy facies of the Cenomanian at the White Hart Sandpit, Wilmington, 
S. Devon. The burrows are in the equivalent of bed B. of the coastal sections, 
arising from the erosion surface at the top of this division and filled with the overlying 
sandy glauconitic Middle Chalk. The walls of these burrows, like the associated 
T. paradoxica have a phosphatic veneer and the sediment immediately surrounding 
the burrows is impregnated with glauconite. 

Similar burrows have been described and figured by Lessertisseur (1955) from the 
Eocene (Bartonian) of the Paris Basin and by Maubeuge & Lanly (1952) from the 
Bathonian of the Vosges. A similar but much smaller form occurs in the Folkestone 
Beds (Lower Albian) away from the coastal type section, as at Aylesford (Kent), 
and in the Woolwich Bottom Bed (Eocene) at Upnor, (Kent). Some of the specimens 
of Cylindrites spongioides figured by Goeppert (1842, pl. 46, figs. I-4) may be burrows 
of this type. 

These burrows are very similar to those of intertidal crustaceans from the East 
Indies described by Verwey (1930), and are here interpreted as the work of crusta- 
ceans, although it is not implied that these were intertidal. 


OccuRRENCE. Top of Wilmington Sands (bed B), filled with Middle Chalk; 
White Hart Sandpit, Wilmington, S. Devon. Similar burrows occur in the bioclastic 
Santonian of the Sudmerberg near Goslar on the north flank of the Hartz (J. M. 
Hancock, personal communication). 


Burrow Type C 
(Text-fig. 7) 


DEscRIPTION. Long, straight or slightly flexed, very narrow cylindrical burrows 
up to 40 cm. long and between r and 10 mm. in diameter. Both vertical and hori- 
zontal elements occur, the latter often much narrower than the vertical part, from 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 159 


A 


) : 


Fic. 7. Burrow type C. a-—p, Lower Chalk, Middle Cenomanian; Glynde, Sussex. E-F, 
Lower Chalk, Upper Cenomanian; Dorking, Surrey. All specimens in relief on vertical 
solution planes. All x}. 


GEOL. I5, 3. 16§ 


160 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


which they branch off at right angles. Some of these burrows curve round to a 
horizontal position and have tunnels 10-25 cm. long. 


Discussion. Burrows of this type are best seen on vertical solution planes, 
where they frequently stand out in relief. From their abundance on such surfaces 
they are clearly responsible for much of the sedimentary mottling seen in the Lower 
Chalk. 

Some fragments compare with Lennea Krausel & Weyland (1932, 1934, Paulus 
1957, Hantzschel 1962, 1965) from the Devonian of Germany, but are generally 
smaller and lack the diagnostic bifurcation of the lateral tunnels. 

It would seem reasonable to regard this form of burrow as produced by worms or 
some worm-like animal. 


OccuURRENCE. Present in all sections in the Lower Chalk examined, particularly 
in the upper part where they are prominent on vertical solution planes. 


Burrow Tyre D 


GENS Bytes JOB G/ites, 3 71 by) JLo), les 5) 


1897 Terebella lewesiensis (Mantell); Davies : 145-148 (pars.). 
1g11t_ ‘‘ Tevebella’’ cancellata Bather : 551-553 (pars.), pl. 24, fig. 5 only. 


DESCRIPTION. Vertical and horizontal cylindrical burrows, straight or slightly 
sinuous, unbranched so far as is known, between 5 and 25 mm. in diameter. Frag- 
ments only known, up to 20 cm. long. Surface covered in long, fine, straight or 
slightly spiral longitudinal ridges, also bearing coarser longitudinal folds. 


Discussion. As already noted, material described by Bather (r911) as “ Tere- 
bella’”’ cancellata includes two distinct forms. The forms considered here are those 
bearing fine longitudinal ridges, interpreted by Bather (p. 552) as follows: “ It seems 
quite certain that these fossils represent tubes, which lay on the sea-floor or in the 
semi-floating ooze of which it consisted, and, either being deserted by the creature 
that formed them or persisting after its death and decay, were filled with the ooze in 
which they lay. The tube wall it is clear, was of such strength and consistency as to 
retain its form fairly well during this process, and yet of such composition that it 
disappeared after the partial consolidation of the ooze. The markings on the infilling 
of the tube may be due to two causes; either a similar folding of the tube-wall during 
life or a wrinkling and contraction of the tube after death and perhaps even after 
burial. ... the irregularity and variable development of the folds suggest that they, 
at least, were due to post-mortem change ’’. 

My own view is that these are burrows, and that they never existed as free tubes 
on the surface. 

The surface features of these burrows can be interpreted as the result of two 
different processes. The fine ridges, I would interpret as the result of some worm-like 
animal passing through sediment, the ridges arising from bristles or appendages, or 
even grains of sediment stuck on the body. The longitudinal folds have a quite 
different origin and appear to be post-depositional compaction effects. 


LOWER CHALK TRACE FOSSILS OF S. ENGLAND 161 


Clearly, there is no similarity to the reticulate surface ornamentation of the holo- 
type of “ Terebella”’ cancellata. 

A rather similar ornamentation is present on the “ fucoids ”’ Gyrolithes dewalquei 
Saporta (Saporta 1884) Codites neocomiensis Saporta & Meunieur (Saporta 1882) 
and Cylindrites rimosus Heer (Heer 1877). 


OCCURRENCE. Common in all sections examined in the Weald, Isle of Wight and 
Chilterns. 


BurRow TYPE E 
(Qed, Agate, &}) 


DESCRIPTION. Cylindrical burrows, generally 1-2 cm. in diameter, known only 
from unbranched fragments. Sections show the filling of these burrows is septate, 
being made up of meniscus-shaped laminae. 


INTERPRETATION. Burrow-fillings showing this type of lamination can be pro- 
duced by a number of groups. Thalassinoides occasionally show this type of filling, 
as do other undoubted crustacean burrows, such as Ophiomorpha. The same type 
of structure can be produced by coelenterates (Schaefer 1962 : 326, fig. 165), 
echinoids (Schaefer 1962 : 348, fig. 183) and some bivalves (Schaefer : 424, fig. 223). 
Under the conditions of chalk sedimentation, and by comparison with other forms, 
these are probably crustacean burrows. 


OcCURRENCE. Uncommon in all sections of the Lower Chalk examined. 


Many other trace fossils are represented in the Lower Chalk. “ Terebella” 
lewesvensts (Mantell), worm tubes lined with fish, plant or echinoderm debris should be 
interpreted as trace fossils, as should the micro-coprolites described by Wilcox 
(1953) from the Upper Chalk, which also occur in the Lower. Borings, in shells, 
pebbles and rock surfaces are very abundant. In addition to species of Clona, 
other sponge borings (Filuroda), algal and fungal perforations (Calcidelectrix, Dictyo- 
porus), cirripede bores (Zapfella, Rogerella), bryozoan borings and bivalve crypts all 
occur. 


VI. CONCLUSIONS 

The activities of burrowing organisms are shown to be universally present in the 
Lower Chalk. The most obvious are those of crustaceans (T/alassinoides, Spongelio- 
morpha) and “worms” (Chondrites). Several poorly known burrows are also 
described. Of previously described assemblages, the present one compares best 
with the Lower Lias (Hallam 1961), where both Chondrites and Thalassinoides occur. 
U-shaped burrows (Riuzocorallium etc.), common in the Lower Lias, are, however, 
absent in the Chalk. 

A problem of the Lower Chalk fauna, in view of the abundance of burrows, is the 
absence or great rarity of the animals responsible. With worms, disappearance of 
the soft body is readily understood, but the absence of crustaceans demands explana- 
tion. The crustacean fauna of the Lower Chalk is very limited. By far the most 


162 LOWER CHALK TRACE FOSSILS OF S. ENGLAND 


abundant form is the large, lobster-like Enopfloclytia, though the very massive 
claws and thick, thorny carapace suggest that it did not burrow. The only other 
macrurous crustacean I have seen is Glyphea willeti (Woodward), which, in view of 
the thin, rather delicate exoskeleton, could well have burrowed. In size, it would 
fit some of the larger Thalassinoides, but itisrare. Callianassids, recorded in associa- 
tion with Thalassinoides elsewhere, appear to be totally absent from the Lower 
Chalk facies of the Cenomanian, although a “ Callianassa’”’ sp. is present in division A 
of the Cenomanian Limestone of S. Devon. Hume (1897) records a Callianassa sp. 
as occurring commonly in the Upper Glauconitic Beds (Cenomanian) at Colin Glen, 
Co. Antrim. Callianassids also occur in the Upper Greensand of the Devon Coast 
(matrix of museum specimens suggests the Top Sandstones) and the Gault. 

Brachyurous crustaceans are equally rare; a few specimens of Dzaulax and 
Necrocarcinus are known from the Lower Chalk, whilst crabs are not uncommon in 
the sandy facies of the Cenomanian, particularly at Wilmington. In all, the known 
crustacean remains give few clues to the identity of the burrowers. A possible 
explanation of absence is suggested by recent burrowing forms which have a thin, 
sometimes even transparent exoskeleton, very poorly calcified. Sloughs are generally 
removed from burrows, whilst moribund individuals leave their burrows prior to 
death. 

Under these conditions it seems possible that on the Lower Chalk sea floor the 
organically-rich remains were completely eaten or destroyed by scavengers and 
micro-organisms prior to burial. 


VII. ACKNOWLEDGMENTS 

I am grateful to Dr. J. M. Hancock and Dr. J. D. Taylor for reading the manuscript 
of this paper and for making many helpful suggestions. I have profited from dis- 
cussions with Dr. R. Bromley, Dr. C. V. Jeans, Dr. R. P. S. Jefferies and many others; 
Mr. P. Palmer kindly provided me with photographs of the types of Terebella cancellata 
and T. harefieldensis; Mr. R. Cleevely has aided me greatly in finding some of the 
more obscureliterature. Dr. H.W. Ball, Mr. S. Ware and Dr. C. L. Forbes have kindly 
allowed me to examine material in their care, whilst Dr. Jefferies has generously 
allowed me to work on his collection, now in the Sedgwick Museum. Mr. B. 
McWilliams of the Norwich Castle Museum searched the collections for type material 
of T. parvadoxica. Preparation of illustrations by the Technical Staff of King’s 
College, under the direction of Mr. E. O. Rowlands is acknowledged, particularly the 
assistance of Miss M. Baker in preparation of the plates. I am deeply grateful to 
my parents for their encouragement and assistance. 

Part of the work was carried out under the tenure of a N.E.R.C. grant, which is 
gratefully acknowledged. 


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12a Dy -N Aa Dane 


Fic. 1. Thalassinoides saxonicus (Geinitz). Lower Chalk, Middle Cenomanian; Houghton 
Regis, near Dunstable, Beds. Base ofa fallen block of Totternhoe Stone with part of the under- 
lying Chalk Marl attached, the burrow is filled by Totternhoe Stone. Plan view, hammer head 
16 cm. long. 

Fic. 2. Thalassinoides cf. suevicus (Rieth). Upper Greensand; Cow Gap, N.E. of 
Beachy Head, Eastbourne, Sussex. Burrow originates from the base of the Glauconitic Marl 
(Lower Cenomanian). Plan view, scale in inches. 

Fic. 3. Burrows at base of the Glauconitic Marl, Lower Cenomanian; Compton Bay, Isle of 
Wight. Vertical section, hammer head 16 cm. long. 

Fic. 4. Laminated structures. Lower Chalk, Middle Cenomanian, bed 7; foot of cliff 600 m. 
E. of Akers steps, Dover, Kent. Vertical section, pencil 9 cm. long. 


Bull. By. Mus. nat. Hist. (Geol.) 15, 3 PALE 1 


GEOL. 15, 3. 17 


PLATE 2 


Fic. 1. Spongeliomorpha? annulatum ichnosp. nov. Glauconitic Marl, Lower Cenoma- 
nian; foreshore, East Wear Bay, Folkestone, Kent. Oblique section, hammer head 16 cm. long. 

Fic. 2. Vertical section of burrowed chalk with abundant Chondrites sp. Lower Chalk, 
Upper Cenomanian; Betchworth Limeworks, Betchworth, Surrey. x1. 

Fic. 3. Vertical section of burrowed chalk with Chondrites sp. and burrow type E. Lower 
Chalk, Middle Cenomanian; Eastbourne, Sussex. XT. 

Fic. 4. Vertical section of burrowed chalk. Lower Chalk, Upper Cenomanian; 
Kent. Note relative abundance of Chondrites sp. in larger burrows. XI. 


Dover, 


Bull. By. Mus. nat. Hist. (Geol.) 15, 3 


GEOL. 15, 3. 


PLATE 3 
Thalassinoides paradoxica (Woodward) 


Neotype, B.M. (N.H.) 7.545. Lower Chalk, Lower Cenomanian, Pavadoxica bed; Hunstan- 
ton, Norfolk. Oblique view, scale in centimetres. 


PLATE 3 


Bull. By. Mus. nat. Hist. (Geol.) 15, 3 


PLATE 4 
Thalassinoides paradoxica (Woodward) 


Neotype, B.M. (N.H.) T.545. Lower Chalk, Lower Cenomanian, Paradowica bed; Hunstan- 
ton, Norfolk. Plan view, scale in centimetres. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 3 PLATE 4 


PLATE 5 


Fic. 1. Laminated structure showing disruption of lamination by subsequent burrowing. 
B.M. (N.H.) T.550, Lower Chalk, Middle Cenomanian; Pit N.E. of Wouldham Hall, Wouldham, 
Kent. Vertical section, x1. (Detail of Pl. 8, fig. 3). 

Fic. 2. Thalassinoides saxonicus (Geinitz). B.M.(N.H.) 17.547, Lower Chalk, Middle 
Cenomanian, chalk beneath Totternhoe Stone; Houghton Regis, near Dunstable, Beds. Plan 
view of upper surface of termination showing ornamentation of elongate mounds. x $. 

Fic. 3. Thalassinoides saxonicus (Geinitz). B.M.(N.H.) 1.548. Same horizon and 
locality, detail of figured specimen (PI. 6, fig. 3), showing bottom covered with Chondritessp. XT. 

Fic. 4. Burrow type D. S.M.C. b92473 (Jefferies collection). Plenus Marls, bed i; Merst- 
ham, Surrey. XT. 

Fic. 5. Spongeliomorpha? annulatum ichnosp. noy. Holotype, B.M.(N.H.) 1.554. 
Glauconitic Marl, Lower Cenomanian; section below Martello Tower no. 3, Copt Point, 
Folkestone, Kent. x1. 


All specimens except Fig. 1 coated with ammonium chloride. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 3 PLATE 5 


PLATE 6 


Fic. 1. Pseudobilobites jefferiesi ichnosp. nov. B.M. (N.H.) T.556. Lower Chalk, Upper 
Cenomanian; 7 m. below top of bed 8, base of Shakespeare Cliff; W. of Dover, Kent. Bottom 
surface, XI. 

Fic. 2. Cylindrical burrow full of coarse debris. S.M.C. Bg2827 (Jefferies collection). Plenuws 
Marls, bed i; Merstham, Surrey. Listed by Jefferies (1963) as Problematicum sp. XT. 

Fic. 3. Thalassinoides saxonicus (Geinitz). B.M.(N.H.) 7.548. Lower Chalk, Middle 
Cenomanian, chalk beneath Totternhoe Stone; Houghton Regis, near Dunstable, Beds. Bottom 
surface of typical branching fragment covered with Chondrites sp. XT. 

Fic. 4. Thalassinoides ornatus ichnosp..noy. associated with T. saxonicus (Geinitz). 
Holotype B.M.(N.H.) 7.559. Same horizon and locality. Top surface, x1. 


All specimens coated in ammonium chloride. 


PLATE 6 


Bull, Br. Mus. nat. Hist. (Geol.) 


PLATE 7 


Fic. 1. Burrow type D. B.M. (N.H.) 7.557. Lower Chalk, Middle Cenomanian, horizon 
of abundant Ovbivhynchia mantelliana (Sowerby) and Sciponoceras baculoide (Mantell); 
Beddingham Limeworks, Beddingham, near Glynde, Sussex. XT. 

Fic. 2. ‘ Terebella”’ harefieldensis White. Holotype, B.M.(N.H.) A.2445. Chalk/ 
Reading Beds junction; The Great Pit, Harefield, Middlesex. x1. 

Fic. 3. Pseudobilobites jefferiesi ichnosp. nov. S.M.C. Bg1035. Plenus Marls, bed i; 
Merstham, Surrey. Figured Jefferies (1963, pl. 77, fig. 5). Bottom surface, x1. 

Fic. 4. Burrow type D. B.M.(N.H.) T.569, Lower Chalk, Middle Cenomanian; Bluebell 
Hill, Burham, Kent, x1. 

Fic. 5. Burrow type D. B.M.(N.H.) 1.558, Lower Chalk, Middle Cenomanian; Glynde, 
SUSSS xem Gils 

Fic. 6. Thalassinoides ornatus ichnosp. nov. Paratype, B.M.(N.H.) 1.551. Lower 
Chall, Middle Cenomanian, chalk below Totternhoe Stone; Houghton Regis, near Dunstable, 
Bec Sia <te 

Fic. 7. Spongeliomorpha sp. B.M. (N.H.) T.553, same horizon and locality. XI. 


All specimens except Fig. 2 coated in ammonium chloride. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 3 


PLATE 8 


Fic. 1. ‘‘ Terebella”’ cancellata Bather. Holotype, B.M. (N.H.) 58253 (Capron collection). 
Lower Chalk, subglobosus Zone; Glynde, Sussex. Figured Bather (1911, pl. 24, fig. 3). x1. 

Fic. 2. “ Terebella”’ cancellata Bather. Paratype, B.M. (N.H.) A.1574 (Capron collection). 
Lower Chalk; Cowslip pit, near Guildford, Surrey. x1. 

Fic. 3. Laminated structure. B.M. (N.H.) 7.550, Lower Chalk, Middle Cenomanian; pit 
N.E. of Wouldham Hall, Wouldham, Kent. Vertical section, upper surface at left margin. 
x 2. 

Fic. 4. Pseudobilobites jefferiesi ichnosp. nov. S.M.C. Bg1557 (Jefferies collection). 
Plenus Marls, bed 1; Merstham, Surrey. Lower surface, x1. 

Fic. 5. Thalassinoides paradoxica (Woodward) B.M. (N.H.) T.549. Lower Chalk, Lower 
Cenomanian, Pavadowxica bed; Hunstanton, Norfolk. , 


Figures 1-3 uncoated, 4, 5 coated with ammonium chloride. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 3 PLATE 8 


PLATE 9 


Fic. 1. Chondrites sp. B.M. (N.H.) 7.562. Lower Chalk, Middle Cenomanian, horizon 
of abundant Orbirhynchia mantelliana (Sowerby) and Sciponoceras baculoide (Mantell); 300 m. 
west of Head Ledge, N.E. of Beachy Head, Eastbourne, Sussex. XI. 

Fic. 2. Thalassinoides paradoxica (Woodward) B.M. (N.H.) T.546, Lower Chalk, Lower 
Cenomanian, Paradoxica bed; Hunstanton, Norfolk. xT. 

Fics. 3,4. Pseudobilobites jefferiesi ichnosp. nov. Holotype B.M. (N.H.). T.565. Lower 
Chalk, Middle Cenomanian, chalk below Totternhoe Stone; Pitstone, Buckinghamshire. 3, 
upper surface, 4, lower surface. XI. 

Fic. 5. Burrow type D. S.M.C. Bg2472 (Jefferies collection). Plenus Marls, bed i; Merst- 
ham, Surrey. 

Fic. 6. Pseudobilobites jefferiesi ichnosp. nov. S.M.C. Bg91653b (Jefferies collection). 
Plenus Marls, bed 1; Lockinge, Berkshire. 


All specimens except Figs. 1 and 6 coated with ammonium chloride. 


Bull. Br. Mus. nat.'Hist. (Geol.) 15, 3 PLATE 9 


\\ 


PRINTED IN GREA 
BY ADLARD & so 


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12 Jan 


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M. E. J. CHANDLER 


a BULLETIN OF 


Ook : 1968 


TUN wea > :y 


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A NEW TEMPSKYA FROM KENT 


BY 


MARJORIE E. J. CHANDLER 


Kv 


Pp. 169-179; 12 Plates 


BULLETIN OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 
GEOLOGY Vol. 15 No. 4 
LONDON : 1968 


THE BULLETIN OF THE BRITISH MUSEUM 
(NATURAL HISTORY), instituted in 1940, 1s 
issued in five series corresponding to the Departments 
of the Museum, and an Historical series. 


Parts will appear at irregular intervals as they become 
ready. Volumes will contain about three or four 
hundred pages, and will not necessarily be completed 
within one calendar year. 


In 1965 a separate supplementary series of longer 
papers was instituted, numbered serially for each 
Department. 

This paper is Vol. 15, No. 4 of the Geological 
Palaeontological series. The abbreviated titles of the 
periodicals cited follow those of the World List of 
Scientific Periodicals. 


World List abbreviation 
Bull. Br. Mus. nat. Hist. (Geol.). 


© Trustees of the British Museum (Natural History) 1968 


DRUSTEES) OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 


Issued 12 January, 1968 Price £1 10s 


A NEW TEMPSKYA FROM KENT 


By M. E. J. CHANDLER 
MS accepted 18th April, 1967 


SYNOPSIS 


A silicified specimen with well-preserved cell structure, found on the shore at Sheppey, proves 
to be a new species of the Mesozoic “ genus ”’ Tempskya in which individual solenostelic stems are 
welded together into a “‘ false stem ”’ by their intertwining roots. Detailed morphology links 
this specimen most closely with Tempskya grandis from the Upper Cretaceous of Wyoming but 
the two are distinguished by the greater number of meristeles normally present within the rhi- 
zome section of the American species and the great difference of size. 


The type of siliceous preservation suggests that the specimen may have come from the 
Woolwich Beds of Herne Bay. 

The Kent Tempskya is only the second species to be recorded from England and is quite 
distinct from the well known Tempskya evosa found in the Wealden Beds and the Lower Green- 
sand. 


INTRODUCTION 


SOME years ago a member of the United States Geological Survey, Dr. R. A. Scott, 
paid a visit to the Sheppey coast to see this famous source for London Clay plants. 
He picked up, lying loose on the shore, a somewhat waterworn “ stem ”’ and kindly 
gave it to the British Museum (Natural History). A transverse cut just below the 
apex of the specimen (V.51841) showed that it was a fern beautifully preserved in 
silica with excellent cell structure. The siliceous preservation raised the question 
of the origin of this plant so unlike the London Clay fruits and seeds which are 
commonly pyritized, occasionally carbonaceous or with calcitic internal casts and 
not infrequently a mixture of pyrites and carbonaceous tissues. The specimen has 
now been studied and the results of the investigations are described below. 


DESCRIPTION OF SPECIMEN 


The silicified “ false stem ”’ was originally about 12:5-13 cm. long. The cutting 
process when the apex was severed of course involved some loss of length. Both 
parts of the specimen have now been examined, further cuts have been made, and a 
few thin sections have been prepared. The specimen is now in four fragments. The 
poorly preserved basal part is numbered V.51841, the central part V.51841a; 
and the apex, which has further been cut longitudinally into two fragments, 
V.51841b andc. Of the six slides (V.51841d-1), V.51841d from the top of V.51841 
is too ill-preserved to be very informative or worth thinning. V.51841e and f 
are from the upper surface of V.51841a, the slide e being lower than f. Slides 
V.51841 g, h and come from the base of V.51841b. They do not extend across the 
whole breadth of the specimen nor even of the cut surface of V.518410, but all three 
together with 61 and 2 lie within about 10 mm. of the length of the ‘“ stem”’. 


GEOL. I5, 4. 18§ 


172 A NEW TEMPSKYA FROM KENT 


The transverse diameter of the whole specimen at broadest (i.e. at about the middle) 
is 5.4 by 3.5cm. In its rolled and waterworn state it shows superficially a complex 
of stems with general longitudinal alignment and some evidence of dichotomous 
bifurcation and intertwining, (Pl.1, figs. 1,2). Remains of a few projecting 
scattered petiole bases are seen (PI. 1, fig. 2; Pl. 2, fig. 4). Section V.51841/ passes 
through one stem in the early stages of dichotomous division (PI. 1, fig. 3; Pl. 3, 
fig. 6; Pl. 4, fig. 7) so that there are two steles but both are still surrounded by a 
single cortex and epidermis which have become somewhat bilobed. The whole 
specimen is more abraded on one broad surface than on the other. Some crushing, 
dislocation and disintegration can be detected in the section towards this worn side 
making the structures more obscure here than elsewhere. There has been some 
disruption of the stele, for example, in the dividing stem (PI. 3, fig. 6; PI. 4, fig. 7). 
A few deep concavities show the surface view of ramentae in lighter coloured silica 
(Pl. 1, fig. 1). They are obscured by abundant freely branching roots many of which 
grew upwards. The fringed edges of the scales, due to their multi-cellular structure, 
show clearly in places. Despite wear and tear the specimen appears to retain, 
approximately at least, the original length and breadth, for emerging petiole bases 
project from the general surface both on the side and at the apex. The structure, 
at the lower end where amorphous silica has obliterated cell tissues, is more obscure 
than in the upper two-thirds of the specimen. More especially is this the case on the 
less well preserved side. 

In transverse section in the upper part (PI. 1, fig. 3) all or part of seven radially 
arranged dorsiventral stems are visible. They show a typical solenostelic structure. 
Five of them are closely adjacent to or actually at the circumference; two are more 
deeply embedded but still radially aligned. In all, the steles are towards the inner 
end of a radial line, and the leaf traces or meristeles at their outer ends. The spaces 
between the stems are packed closely with ramentae and roots of various sizes. The 
latter may be sectioned longitudinally for a short distance but are commonly 
transversely or obliquely cut in the slides and cut surfaces. The penetrating roots 
which pierce the scales and weave in and out weld the stems into the “ false stem ”’. 
The solidity of the whole complex is undoubtedly enhanced by the process of silicific- 
ation which unites stems, scales and roots into a solid inseparable mass, silica 
penetrating all tissues and replacing cell contents just as in Osmunda dowkert. 

The maximum transverse diameter of the component stems is about 15.5 by 
g mm., or 15 by 11 mm. in the middle of the specimen, larger, some 22 to 25 by 
II mm., in the basal part. Near the apex some stems are smaller, 12 or 13 by 8 mm., 
but others are 15 by 13 and 16 by 1m mm. 

In addition to the roots which belong to the fern itself, numerous “‘ foreign ”’ roots 
are visible in the sections. In particular they are concentrated in an irregular but 
continuous thin belt of sclerenchyma outside, concentric with and close to the steles 
and meristeles. They make this belt of tissue very conspicuous while often obscuring 
its detailed structure. They are also abundant in the sclerenchyma of the pith 
adjacent to the leaf gaps (Pl.5, fie: Pl}7,tigs10; PIS; fie 11; Plo ropiietane): 
Some of these roots may be monocotyledonous, others dicotyledonous, as they show 
radially arranged small xylem cells containing large scattered vessels. I am indebted 


ANEW DEMPSKYA PROM KENT 173 


to Dr. Holttum for these suggestions. The roots sometimes take the place of the 
stelar tissues of the fern roots within a dense belt of surrounding sclerenchyma. 

Structure of individual stems. The stems are clearly solenostelic. Some 
sections show a complete cylinder with no leaf gap (Pl. 8, fig. 11), others show a 
single leaf gap (PI. 7, fig. 10; Pl. 9, fig. 12). Yet others have two leaf gaps (Pl. 5, 
fig. 8; Pl. 6, fig.9). The pattern due to the development of the leaves is repeated at 
regular intervals in the individual stems so that the sections made at different levels 
across the false ‘‘ stem ’”’ show successive changes. In any single section the in- 
cluded stems are commonly at different stages in development. Intermediate stages 
have been seen on the polished surfaces exposed both before and after section 
cutting but being unsuitable for photography they are not represented in the 
plates. 

The periphery of the stems, inside an ill-preserved epidermis from which the 
ramentae arise, is formed of several layers of opaque sclerenchymatous cells with dark 
contents. Up to a dozen layers have been counted. Exactly similar outer tissues 
are described by Read & Brown (1937 : 110) in Tempskya grandis as the “ outer 
cortex’. Within is a layer of sclerenchyma, at least twenty cells thick, cells which 
although thick-walled retain a considerable lumen. It clearly corresponds with the 
“middle or sclerenchymatous cortex’ in T. grandis. Individual cells are isodia- 
metric in cross section where the walls appear to be unevenly patchily thickened. 
Inside again occurs a thick layer, twenty or more cells thick, of thin-walled paren- 
chyma (corresponding to the “‘ inner cortex” of T. grandis). It is at least as broad 
as and may be broader than the middle sclerenchymatous cortex. Almost invariably 
the individual cells show black rounded objects occupying much of the cavity; 
sometimes these objects themselves lie in a rounded cavity within the cell. Under 
the quarter-inch lens most of them appear to be agglomerated crystals, although a 
few simple crystals are seen. In longitudinal sections of the cells they appear as 
clumps of elongate crystals with their long axes at right angles to the longer axes 
of the cells. Similar inclusions occur sparsely in the sclerenchyma of the middle 
cortex. Towards the inner margin of the parenchymatous zone there is always a 
continuous narrow band of sclerenchyma very irregular in thickness and therefore 
in outline as seen in transverse section. It may be sharply delimited from the 
parenchyma in which it lies by a dark line on the outer side, (Pl. 5, fig. 8; Pl. 8, 
fig. 11; Pl. 9, fig. 12), but less sharply from three or four layers of parenchyma cells 
which lie between it and the stele. These innermost parenchyma cells are rather 
small but display the same crystalline inclusions. They also occur abundantly in 
the irregular sclerenchyma belt just described, a belt seen only in T. grandis among 
the well preserved fossil species and in the less well preserved 7. superba Arnold. 

The stele is bounded both externally and internally by an endodermis and associ- 
ated tissues. In places the endodermis is well defined as a single layer of equiaxial 
cells. Inside it, preserved only in certain places, are two or more layers of tangenti- 
ally elongate thin-walled cells with clear cavities (Pl. 11, fig. 14). They probably 
represent pericycle and phloem but no sieve plates appear to be preserved. The 
xylem varies considerably in thickness from about three tracheids in depth to sixteen 
or twenty as a result of leaf trace formation. Along the margins of the xylem are 


ce 


174 A NEW TEMPSKYA FROM KENT 


patches of very small tracheids, some certainly showing scalariform thickening. The 
bulk of the xylem is composed of conspicuous large metaxylem tracheids with multi- 
seriate thickening which causes them to appear angular in transverse section so 
producing a characteristic pattern. Where roots are about to arise the small elem- 
ents at the margin become more numerous causing an outward bulge in the endo- 
dermis. It is probable that some of these are protoxylem but no spiral thickening 
appears to be preserved. A considerable amount of parenchyma, often with 
crystalline inclusions is scattered among the tracheids, again as in T. grandis. 
T. rossica and T. wesseliit also show this feature (Andrews & Kern 1947 : 147) as 
does T. superba (Arnold 1958 : 137). Where the stele becomes thin and the bulge 
which initiates a leaf trace begins to form, the metaxylem tracheids follow a tangen- 
tial course (PI. Io, fig. 13). In the actual slide they then show the thickening clearly. 
At one leaf gap the end of the stele abutting on it shows what appear to be some 
spiral tracheids near the margin of the xylem. 

Where the pith within the stele adjoins the endodermis there is a thin layer of 
parenchyma with the usual inclusions. It is continuous through the leaf gap with 
the fine parenchyma which bounds the stele externally. Otherwise almost the 
whole pith is formed of sclerenchyma with thick-walled cells, and, at the centre, with 
little lumen (PI. 5, fig. 8; Pl. 7, fig. 10). The sclerenchyma is also continuous through 
the gap with the sclerenchyma of the cortical zone of the rhizome. 

Scales or Ramentae. These may be very broad. One which could be measured is 
at least Io mm. wide. The elongate cells which form them lie end to end and side to 
side. In the rows of cells the end walls are transverse or oblique to the length. The 
cell rows diverge towards the lateral margins of the scales where the free ends of the 
rows separate and form the characteristic fringed edge. Seen in transverse section 
of the stems they appear as thin multicellular plates of tissue (Pl. 2, fig. 5; Pl. 7, 
1H, 3). 

Development of leaf traces and structure of meristele. On that side of the stele 
towards the circumference of the “‘ false stem ’’, leaf gaps arise at short longitudinal 
intervals indicating that the leaves must have been crowded. Im a single section 
across one stem two and sometimes three leaf-traces may still be included within the 
cortex and epidermis showing that they arise at acute angles (Pl. 3, fig. 6, stem 0; 
Pl. 9, fig. 12). Once they have emerged from the stem they apparently change their 
direction and pass out of the “ false stem ”’ quickly. An occasional projecting leaf 
base on the side of the upright “‘ false stem ”’ (Pl. 1, fig. 2) points to the fact that they 
were borne at intervals along its length. A terminal crown may also have occurred 
(Pl. 2, fig. 4). The appearance of the stele in transverse section varies with the 
degree of development of the leaf trace, the positions of the leaf gaps and meristeles 
in successive sections suggesting that they were borne in two somewhat irregular 
rows. The stages in trace formation have been pieced together from the various 
stems in thin sections and cut surfaces. Serial sections were not attempted because 
there is only one specimen and its preservation is so patchy. This caused the 
sections to break irregularly and made complete transverse slices difficult to obtain. 
It also limited the amount of thinning that could be carried out. 

Development of a trace is heralded first by the thinning of part of the stele con- 


A NEW TEMPSKYA FROM KENT 175 


nected with its formation while simultaneously an adjacent protuberance occurs 
(Pl. 6, fig. 9, rhizome a; Pl. 7, fig. 10). The bulge or protuberance then develops 
a pair of angular thickenings on the inside of the stele near its inner limits (PI. 3, 
fig. 6, rhizome 6). Further thinning at the inner ends of the bulge just beyond 
the thickened angles now produces a gap, first on one side and then on the other 
(Pl. 7, fig. 10). Asa result a C-shaped trace opening inwards is separated from the 
stele (Pl. 9, fig. 12; cf. Pl. 6, fig. 9, rhizome a with PI. 7, fig. 10). The trace passes 
upwards and outwards through the cortex. The angles on the inner side of the stele 
soon become elongated tangentially and approach one another fusing as they pass 
up the stem with resulting restoration of the complete cylinder. 

At certain stages of development two gaps are seen in a single transverse section. 
In this case a semicircular section of the stele with its flattened surface towards the 
periphery of the “ false stem ”’ gives rise to thin outward curving lobes at its angles. 
The lobes separate first from the central area remaining attached at their inner ends 
and so producing a double convex curve on each side, the curve of the developing 
trace being much shorter than that of the parent stele. The central fragment of stele 
which may be simple or bilobed then appears as an island separated from the main 
stele by two developing leaf gaps (Pl. 5, fig. 8; Pl. 6, fig. 9, stem 0). Usually one 
trace becomes detached as on the right in PI. 6, fig. 9, while the other still remains 
attached although much thinned and ready for almost simultaneous separation. 

Recently emerged leaf traces soon form elongate bulges on the stem surface even 
prior to their complete departure from it (PI. 5, fig. 8, cf. min Pl. 7, fig. 10 and in 
Pl. 9, fig. 12). The final separation of the trace as it passes through the cortical 
tissues next occurs. A tongue of sclerenchyma grows inward between stem and 
trace, one side giving off a branch which enters the bay of the meristele. Scleren- 
chyma from the opposite side also extends inwards until the two sides meet thereby 
completely surrounding both stem and leaf base (m in PI. 7, fig. 10). At a slightly 
higher level the outermost stem tissues grow in also and divide sclerenchyma of stem 
and leaf base so that they completely part company (f in PI. 7, fig. 10) the trace 
continuing upwards and outwards until it emerges at the surface of the “‘ false stem ”’. 

In shape the meristele becomes markedly incurved as it passes out of the stem 
(contrast the three meristeles in Pl. 9, fig. 12) while simultaneously its ends thicken. 
As is to be expected, the succession of tissues is as in the stem itself. The meristele 
may be only one or two tracheids thick at the middle of the arc but there are up 
to about seven at the incurved ends. Endodermis and associated tissues completely 
surround it. Owing to the angle at which traces arise transverse sections cut them 
somewhat obliquely so that the tissues appear blurred. The thin parenchyma which 
completely encircles the stele of the leaf trace and its irregular sclerenchyma is 
continuous with the parenchyma of the stem until separated by the ingrowing of the 
sclerenchyma. As in the stem the cells of this tissue show the characteristic 
crystalline inclusions. 

An unexplained peculiarity is seen in the meristele of one thin section. Some of 
the tissues, more especially the parenchyma cells, have broken down and in their 
place oval opaque black bodies can be seen. Similar structures in a root of Tempskya 
knowltont from Montana are described and figured by Seward (1924 : 494, pl. 17, 


176 A NEW TEMPSKYA FROM KENT 


fig. 24). He was unable to explain them but suggested that they might be coprolites 
of a small insect or possibly escaped cell contents. Certainly in the Kent specimen 
each such body occupies a separate cell until the surrounding cell walls have actually 
broken down. Seward adds that entomologists he consulted were unable to identify 
the bodies with the activities of any known boring animal and no trace of any insect 
had been found. “ They consist ’’, he stated, “ of finely comminuted plant debris or 
dark masses of rounded cell contents and are certainly not spores ”’. 

The roots (Pl. 2, fig. 5). These vary greatly in size and are branched repeatedly. 
Some are as much as 2mm. broad. Many roots and their branches grow upward 
through the tissues. They show a small stele with typical diarch arrangement, a 
well-defined endodermis surrounding it. There areabout four to six large metaxylem 
tracheids, flanked at opposite poles by groups of about three to six small protoxylem 
tracheids. The metaxylem tracheids may be 0-027 mm. or less in diameter. Phloem 
is rarely preserved. Outside the endodermis are several layers of concentrically 
arranged sclerenchymatous cells with well developed cavities. They are succeeded 
further out by a thick band of dense sclerenchyma with cavities obliterated. In 
transverse section these cells appear both radially and concentrically aligned forming 
a very conspicuous band of tissue which may be 0-3 mm. broad. It corresponds to 
the ‘‘ middle cortex’ of Andrews & Kern in their description of Tempskya (1947 : 
139). In young roots the sclerenchyma may be less dense. Sometimes outside the 
sclerenchyma there is another concentric belt of thin-walled cells of about the same 
width (Andrews’ ‘‘ outer cortex ’’). It is not invariably preserved. In PI. 2, fig. 5, 
the “ outer cortex ’”’ has a lozenge or diamond-shaped outline of which half only is 
preserved. This shape is dictated by the pressure of closely compacted masses of 
roots in the spaces between the stems. In some roots only the sclerotic tissue 
survives surrounding an empty circular space, occasionally occupied by foreign 
tissues as described above. 

Affinities. The composite character of this “ false stem ’”’ with its dichotomous 
solenostelic true stems embedded in a mass of their own roots and scales connects 
the specimen with the Mesozoic Tempskya of Corda (1845 : 81). Kidston & Gwynne- 
Vaughan (191I : 13) later published a generic diagnosis of the genus quoted by 
Read & Brown (1937 : 108). Unfortunately the true relationship to living ferns 
has not yet been discovered although many distinguished botanists have carried out 
research on the subject. As long ago as 1872 Feistmantel suggested that Tempskya 
was not a genus but a mode of preservation of several distinct types of fern stems. 
To the writer, this view appears to be greatly strengthened by the occurrence of a 
supposed Mesozoic genus in the Tertiary. Read & Brown (1937 : 120) discuss the 
taxomic affinities and summarize views published prior to their paper. They created 
the “ family ’”’ Tempskyaceae as the natural affinities could not be discovered but 
probably no such family exists. It is merely a convenient way of grouping different 
ferns with a similar habit. Dr. R. E. Holttum and Dr. T. G. Walker have kindly 
examined slides or detailed photographs of the Kent fern but were unable to recog- 
nize any living genus with which there is complete agreement. It is necessary to 
remember that the appearance of these plants in life may have differed materially 
from that when fossilized thanks to the cementing and hardening effects of silicifica- 


, 


A NEW TEMPSKYA FROM KENT 177 


tion welding stems and roots into an apparently solid entity. Like Feistmantel, 
Andrews & Kern (1947 : 143) consider that the “ trunk ”’ of the genus “‘ represents a 
peak of structural evolution that is manifest in a generally comparable fashion in a 
number of ferns, both living and fossil”. They refer to scattered references in 
literature, not quoted in detail, to living ferns having an upright trunk composed of 
branching stems “ held together to a greater or lesser degree by a mass of adventiti- 
ous roots’’. Among these are, of course, some of the well-known tree ferns with a 
similar upright trunk or caudex which differ in important respects from Tempskya 
and all of which are certainly much larger than the Kent specimen. Writing later 
Andrews (1961 : 116) after briefly describing the genus commented that the radial 
development suggests a single stem in the early sporeling stage which grew and 
divided to form a large and longer trunk. He did not then consider the anatomy of 
the stem sufficiently distinctive to afford evidence of affinity but again emphasized 
that the mode of growth could have arisen independently in several unrelated 
groups. None known to him agreed closely with Tempskya either in detailed anat- 
omy or in the huge number of stems involved. The smaller size of the Kent 
“false stem ’’ with its fewer true stems strongly suggests that this specimen may 
eventually be matched among living material when sufficient knowledge of the 
anatomy and cytology of this vast group of plants is available and allowance is made 
for the profound alteration in appearance due to silicification. Whatever the 
relationship of the Mesozoic species may be it is most likely that the Kent specimen 
belongs to a living genus. Naturally Recent root stocks and stem bases are not 
available in unlimited amount or variety. The majority of Tempskya species are 
from America which has produced at least seven distinct kinds. Some of these are 
enormous attaining to 16in. in diameter and a height of at least 12 or possibly 
19 or 20 feet. Some include a very large number of stems. Thus Andrews & Kern 
(1947 : 155) quote more than 200 stems in a single trunk. Some of the American 
species are well preserved and fall into two clear groups (Read & Brown 1937 : 119; 
Andrews & Kern 1947 : 147). The Kent “stem” closely agrees in its detailed 
morphology with T. grandis Read & Brown (1937 : 114, pl. 20, fig. 2; pl. 32, figs. 
ea epiee3 5, Hes. 1-4, pl. 34, ties. 1-45) pl. 35, figs. 1-45) pl. 4r, fig: 4; pl. 42; 
figs. 1-3; pl. 43, figs. 1, 4-7) which belongs to the first of these groups. It is an 
Upper Cretaceous species from the Aspen shales of Wyoming. It is about 8 cm. 
in diameter and some 20 cm. long, perhaps larger because more mature than the 
Kent fossil. Despite its somewhat worn appearance, so that one or two of its 
stems are abraded longitudinally on the outer side, it looks as if the whole “ trunk ” 
approximated closely to the original dimensions for the reasons given on p. 172. 
The increased abundance of roots near the base and the failure of preservation of 
other detail in the basal part suggests that this is near to the true base of the speci- 
men which, must, therefore, have been on a much smaller scale than other known 
species. 

Summarizing points of resemblance, some of which have been mentioned in the 
description, the Kent Tempskya and T. grandis have in common: xylem containing 
an appreciable amount of parenchyma; an inner parenchymatous cortex which 
encloses a constant but narrow irregular band of sclerenchyma close to but not 


178 A NEW TEMPSKYA FROM KENT 


contiguous with the stele; a similar narrow zone of parenchyma forming the outer 
layers of pith in contiguity with the stele and with the sclerenchyma inside; large 
individual stems in the false “stem” with rather short internodes. Thus apart 
from difference of size which may not necessarily be of great significance the material 
of the Kent specimen can only be distinguished from Tempskya grandis by the 
smaller number of meristeles in the transverse sections of the rhizomes. It has from 
one to three, commonly two meristeles, whereas in T. grandis there are two to five, 
commonly three or four, implying greater crowding of the leaves in this latter species 
(cf. Read & Brown 1937 : 115, text-fig. 3, pl. 28, fig. 2 [Note the erratum slip]; 
pl. 32, figs. 2-5; pl. 33, figs. 1-4). 

T. superba described by Arnold (1958 : 138) has suffered obliteration of much de- 
tail by complete silicification of the tissues. Form and size of individual stems are 
retained and there is enough structure to show a strong resemblance to T. grandis 
in that both have the distinctive continuous but irregular sclerotic layer in the inner 
cortex absent in other species except the Kent form. All three also have scleren-. 
chyma in the pith. Arnold separates T. superba from T. grandis partly on the much 
larger size of its stems which he gives as at least I cm. in diameter without attached 
leaf bases, 2 cm. if they be included. He infers that the diameter of T. grandis 
(stems) is 6-7 mm. but according to measurements based on Read & Brown’s 
figures the two species appear to approach one another in this respect, while in the 
Kent Tempskya a considerable range of size occurs in the one specimen depending 
on the position within the length of the stem (cf. p. 172). Size of stem alone, there- 
fore, does not appear to be a sufficient reason for separation. The holotype of 
T. grandis is 8 cm. in diameter, 20 cm. long. That of T. superba was a slab measur- 
ing about 6 by 12 cm., 2 cm. thick before cutting. It was obviously very incomplete. 
Both greatly exceed the dimensions given for the Kent specimen (see p. 172). 
T. superba normally shows four or five foliar traces (meristeles) in each stem section, 
indicating, as in 7. grandis exceptionally short internodes. On the grounds of 
number of foliar traces it therefore appears that the Tempskya from Kent is distinct 
from these two species which otherwise it closely resembles in detailed cytology. 
T. superba was found in an eroded Oligocene deposit in Nebraska but is believed to 
have been derived from the Lower Cretaceous Dakota Sandstone. 

As only one specimen from Kent is in existence it is merely described as Temp- 
skya sp. It is the second species to have been discovered in England. A much 
earlier record is T. evosa Stokes, Webb & Mantell from the Wealden Beds or Lower 
Greensand of Tilgate Forest, Hastings and Potton. T. evosa differs completely in its 
character and preservation from Tempskya sp. described here. Its numerous much 
smaller stems show little structure in detail but are embedded in dense masses of 
innumerable roots. It has been re-described and discussed by Stopes (1915 : 16) 
and more recently illustrated by Seward (1924, pl. 16, fig. 4; pl. 17, fig. 16). It is 
so different in every way that it does not concern us here any further. 

Origin of the Specimen. As soon as the specimen was referred to Tempskya it 
raised the question whether a supposed Mesozoic form found at Sheppey could have 
come from the London Clay, especially in view of the silicious preservation (see 
p.171). Mr.G. F. Elliot has pointed out that a similar preservation is known in Palm 


A NEW TEMPSKYA FROM KENT 179 


and dicotyledonous wood, in Osmunda dowkeri and in cones of Pinus macrocephalus 
from Herne Bay. Pinus macrocephalus is occasionally picked up on the shore 
between Bishopstone and Reculvers where the Thanetian outcrop is exposed. Some 
of the above have been attributed to the Thanet Sands, others to the London Clay but 
their preservation is different from that of Tempskya except in the case of the 
dicotyledonous woods from Herne Bay. A few of these (B.M.N.H., V.27923) which 
have closely comparable and characteristic preservation have come from unweathered 
foreshore outcrops of the Woolwich Bottom Bed in Herne Bay. Material washed out 
of the Thanet Sands has been found well to the west of Herne Bay hence Tempskya 
could have been transported naturally to the beach at Sheppey. To summarize, the 
preservation suggests that the Lower part of the Woolwich Beds at Herne Bay is the 
most likely source of the specimen. The difficulty of accepting such a source is 
eliminated if, as seems probable, such a habit of growth is not confined to the Mesozoic 

The photographs were taken in the Photographic Department of the British 
Museum (Natural History). The typing was done by Mrs. M. Firth. To all the 
persons concerned and to those already mentioned in the text the author’s warmest 
thanks are given. 


REFERENCES 


AnpDREwS, H. N. 1961. Studies in Paleobotany. xii + 487 pp. New York. 

ANnpDREwS, H. N. & Kern, E. M. 1947. The Idaho Tempskya and Associated Fossil Plants. 
Ann. Mo. bot. Gdn., 34 : 119-186, pls. 15-27. 

ARNOLD, C. A. 1958. A new Tempskya. Contr. Mus. Paleont. Univ. Mich., 14 : 133-142, 
3 pis. 

Corpa, A. J. 1845. Flora protogaea: Beitrage zur Flova dey Vorwelt. 128 pp., 50 pls. Prague. 

FEISTMANTEL, O. 1872. Uber Baumfarrenreste der bohmischen Steinkohlen, Perm - und 
Kreide-formation. K. béhm. Gesell. Wiss. Abh., 6 : 1-30, pls. I, 2. 

Kipston, R. & GwyNNE-VauGuan, D. T. 1911. Onanew species of Tempskya from Russia. 
Russ. K. min. Gesell. Verh., 48 : 1-20, pls. 1-3. 

Reap, C. B. & Brown, R. W. 1937. American Cretaceous Ferns of the genus Tempskya. 
Prof. Pap. U.S. geol. Surv., 186 : 105-131, pls. 28-43. 

SEWARD, A. C. 1924. On a new species of Tempskya from Montana: Tempskya Knowltoni 
sp. nov. Ann. Bot., 38 : 485-507, pls. 16, 17. 

Stopes, M.C. 1915. Catalogue of the Mesozoic Plants in the British Museum (Natural History). 
The Cretaceous Flora. Part II. Lower Greensand (Aptian) Plants of Britain. xxxvi + 


360 pp. 32 pls. 
DESCRIPTION OF PLATES 


Note. The photographer has taken PI. 1, fig. 3 and Pls. 3-5 from the back of the 
slide. Allowance must be made for this mirror image when examining the plates in 
order to study the development of the stele and leaf traces in the rhizomes. 


IIL NAL ID, it 
Tempskya sp. 


Fics. 1,2. “‘ False stem ’”’ from opposite sides. The apex has been removed. V.51841, 
upper surface of fragment so numbered. Position of slides is at f, g-7. On the left in Fig. 1 
dichotomous forking of the small stems is seen. The white hollow at base shows scales in the 
actual specimen and upwardly directed roots. In Fig. 2 rounded projections at p. are much 
abraded petiole bases. XI approx. 

Fic. 3. Transverse section of “‘ stem’’ somewhat crushed and disorganized in the lower half. 
Seven numbered true stems are visible (part only preserved of 1 and 3), 2 and 7 are embedded in 
roots and scales of “stem ’’ so do not in this section touch the surface of the specimen. 4 is 
in process of dichotomous division, 5 and 6 are rather poorly preserved. X2. V.5184If. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 4 PLATE 1 


GEOL. 15, 4 19 


PLATE 2 
Tempskya sp. 


Fic. 4. Side of severed apical fragment showing projecting petioles at p. Fragment cut 
longitudinally on right in preparing other sections but here shows only roots and scales out of 
focus. X2. V.51841b. 

Fic. 5. Transverse section of typical diarch root penetrating scales arising from the epidermis 
of a stem. Large metaxylem tracheids occupy centre of root and are flanked by two patches, at 
opposite poles, of small protoxylem tracheids. Tissues outside xylem, including endodermal 
ring, decayed (white in figure). Next come three concentric and radial rows of sclerenchyma, 
sc, with cavities. Outside again are four to five rows of dense sclerenchyma cells, d, with 
blocked cavities. A diamond-shaped area (left half only preserved) of thin-walled cells beyond 
the sclerenchyma is cortex, c. The multicellular character of scales, s, can be seen obscurely 
(out of focus). Xcago. V.518411. 


PLATE 2 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 4 


PLATE 3 
Tempskya sp. 


Fic. 6. Part of slide V.51841f shown in Plate 1, fig. 3. The mass of roots and scales in which 
the stems are embedded are sectioned in various directions. Stem 6 (2 in Pl. 1, fig. 3) shows a 
typical cylindrical stele with protuberance on the left marking initiation of a leaf trace. De- 
tached meristeles of two incipient leaf-bases are also seen. Stem a, (7 in Pl. 1, fig. 3) shows a 
stele with two leaf gaps one each side of a small island of xylem. Two curved arms of stele 
indicate leaf traces not yet severed. A stem atc (4 in Pl. 1, fig. 3) which has begun to divide 
dichotomously is, in consequence, bilobed. It is outlined in white but is shown untouched and 
more highly magnified in Pl. 4, fig. 7. The obscure appearance is caused by the partial decay and 
dislocation on this side of the “ stem ’’ but the two new steles are already separated. X5'5. 


PLATE 3 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 4 


PLATE 4 
Tempskya sp. 


Fic. 7. The dividing stem in PI. 3, fig. 6 (the right margin of the figure just cuts the edge of 
the stem). Originally a cylinder the stele on the right has been crushed and consequently dis- 
located in four places. One break passes through the prominence on the left which indicates the 
beginnings of a leaf trace. A meristele which has already separated is seen (surrounded by 
white) below the stele. The second stele in the left lobe of the dichotomy is also distorted but, 
again, the lobe (dislocated) of an incipient leaf trace is visible (above white patch). X Io. 


V.51841f. 


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PLATE 5 
Tempskya sp. 


Fic. 8. The join on the right was due to the stem lying in part on two negatives. 

Stem a in Plate 3, fig.6. Dark band at base crossing cortex and epidermis isa root. The two 
leaf gaps flanking the island of stele are better seen here as are the curved incipient meristeles 
on each side. The curved loop on the left is almost separated but that on the right is still fully 
attached. A deeply curved leaf-trace (top left) is about to emerge. It is already partially cut 
off from the parent stem by ingrowing sclerenchyma from the two sides. Both parent stele and 
meristele are partly embraced externally by an irregular band of sclerenchyma much infested 


with ‘‘ foreign” roots. This belt of tissue is surrounded by parenchyma on both sides. X Io. 
V.5184If. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 4 PLATE 5 


GEOL. 15, 4 


20 


IDILJAANID, (5 
Tempskya sp. 


Fic. 9. Stems a, 6 and in part c show a later (younger) stage of these stems in Plate 3 (re- 
versed aS in a mirror). The stele bounding one leaf gap (in a) has now united again with the 
central island of xylem and forms the loop for a new meristele. The meristele on the left in 
Pl. 3 has separated and moved out into the cortex (right in Pl. 6). The other leaf gap still 
persists. In } the bulge seen on the left in Pl. 3 has separated from the stelar ring (on right in 
Pl. 6); the angular thickenings flanking the bulge in Pl. 3 have elongated and united, but two 
new loops have formed, one on each side of the bilobed fused xylem from which they have 
severed themselves at their upper ends thereby producing two curved loops and two leaf gaps. 
The lower limb in Pl. 6 has just separated from the stem stele. In ¢ the formation of another 
stele is visible. X5. V.51&4Ig. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 4 PLATE 6 


PLATE 7 
Tempskya sp. 


Fic. 10. A yet higher level in stem a. The loop in Pl. 6, top left, has now formed a new 
meristele. The gap in the stele of the stem still persists but another loop at the end of the lower 
free limb is about to initiate another meristele. The leaf trace (top right) is now free from the 
parent stem and is surrounded by its own epidermis. The successive cortical coats (see p. 173) 
are well marked. The irregular sclerenchyma belt within the parenchyma around the stele is 
little infested with “ foreign ’’ roots here, less so than in the young meristele (centre, above). 
The scales arising from the epidermis are well preserved but the magnification is insufficient 
to show the multicellular structure. X10. V. 5184mh. 


Bull. Br. Mus. nat. Hist. (Geol.) 15,4 


PLATE 7 


PLATE 8 
Tempskya sp. 


Fic. 11. Stem 0 at a higher level than in Pl. 6, and differently oriented. The meristele of 
Pl. 6 has separated from the stem and is not shown in this section. The bilobed island of stele 
in Pl. 6 has reunited with the arms of the main stele from which the incipient meristeles, there 
seen as curved extremities, have here separated and moved outwards. The upper of these two 
meristeles is now partly separated from the stem stele by the ingrowing of the outermost band 
of sclerenchyma. ‘“‘ Foreign ’’ roots are clearly shown in the pith sclerenchyma and in that 
outside the main stele itself. The narrow loop of a new meristele is seen on the radius between 


the two separated meristeles. XIo. V. 518411. 


Bull. Br, Mus. nat. Hist. (Geol.) 15, 4 PLATE 8 


PLATE 9 
Tempskya sp. 


Fic.12. A higher section through stema. The loop in the stele in Pl. 7 has separated to form 
a meristele leaving a new leaf gap while the gap seen in Pl. 7 has closed. The curved hook-like 
free end of the stem stele in Pl. 7 has passed out as a meristele (right, below) partially separated 
by ingrowing sclerenchyma. The meristele above in Pl. 7 is now almost separated from the 
parent stem as is evident from the constriction which has formed on each side of it and the 
thick sclerenchyma between the two. The separated trace in Pl. 7 has grown right out of the 
“false stem ’’. The successive coats: epidermis with thin outer cortex, sclerenchymatous middle 
cortex, thick parenchymatous inner cortex with included irregular band of sclerenchyma just 
outside the stele but separated from it by parenchyma, are clearly seen. X10. V.518411. 


PLATE 9 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 4 


12 


PLATE tro 
Tempskya sp. 


Fic. 13. Anarc of the stele in Pl. 8. It shows the large metaxylem tracheids with scattered 
patches of parenchyma among them. Small tracheids are seen at the lower angle of the thicken- 
ed part of the stele above which, to the right, transverse orientation of tracheids is apparent 
where a leaf gap is in process of development. Parenchyma cells with black crystalline in- 
clusions are seen in the inner cortex, and these cells abut on the stele on both sides. Thick- 
walled sclerenchyma with small cavities shows clearly in the centre of the pith but is largely 
obscured by “ foreign ’’ roots in the irregular sclerenchyma belt of the inner cortex outside the 
stele and, in places, in the pith. X35. V.518411. 


Bull. Br. Mus, nat. Hist. (Geol.) 15, 4 PLATE 10 


at ht 


. Pt ww Ad, 
a i AS: nate ; 
sac 

AO Se 
30 : 


‘ 
. 
= 


PEALE, 1 
Tempskya sp. 


Fic. 14. Stelar arc on the opposite side of the stele in Pl. 8. Sclerenchyma cells of the 
irregular band are seen at sc in the parenchymatous inner cortex where “ foreign ’’ roots are 
absent. Small marginal tracheids are well developed in the south-east corner of the stele and 
especially where roots are in process of formation. Tangential cells associated with endodermis 
are visible on the right. Other features asin Pl. 10. X35. V.518411. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 4 PLATE 11 


IPI IRATE, 16 
Tempskya sp. 


Fic. 15. Anarc of stele in Pl. 9, stem a, showing the origin of tworoots. Scales arise from the 
epidermis (top left) where also a large root emerges from the stem. Dense outer cortex is 
visible (top left) sharply differentiated from the sclerenchyma of the middle cortex which in its 
turn is distinct from the parenchyma with black crystalline inclusions of the inner cortex. 
The irregular sclerenchyma belt of the inner cortex lies outside the stele but separated from 
it by a thin layer of the parenchyma. The endodermis is somewhat blurred owing to the slight 
obliquity of the section but can be seen in places in the slide by focusing. Associated tangen- 


tially elongate cells are clear in the slide, obscurely seen in the figure (right, inside stele). X35. 
V .518411. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 4 PLATE 12 


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COLONIAL PHILLIPSASTRAEID 
FROM THE DEVONIAN OF 
SOUTH-EAST DEVON, ENGLAND 


Vel 15 No. 


sss. 1968 


BY 


COLIN THOMAS SCRUTTON A 
eye eh 


Pp. 181-281; 18 Plates; 21 Text-figures 


BULLETIN OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 
GEOLOGY Vol. 15 No. 5 
LONDON: 1968 


THE BULLETIN OF THE BRITISH MUSEUM 
(NATURAL HISTORY), instituted in 1949, 1s 
issued in five series corresponding to the Departments 
of the Museum, and an Historical series. 


Parts will appear at irregular intervals as they become 
ready. Volumes will contain about three or four 
hundred pages, and will not necessarily be completed 
within one calendar ‘year. 


In 1965 a separate supplementary series of longer 
papers was instituted, numbered serially for each 
Department. 


This paper is Vol. 15, No. 5 of the Geological 
(Palaeontological) series. The abbreviated titles of 
periodicals cited follow those of the World List of 
Scientific Periodicals. 


World List abbreviation: 
Bull. Br. Mus. nat. Hist. (Geol.) 


© Trustees of the British Museum (Natural History) 1968 


TRUSTEES OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 


Issued 19 March, 1968 Price £4 


COLONIAL PHILLIPSASTRAEIDAE FROM THE 
DEVONIAN OF SOUTH-EAST DEVON, ENGLAND 


By C. T. SCRUTTON 
MS accepted April 26th 1967 


CONTENTS 

Page 

I. INTRODUCTION ‘ F : . : : : ; : 184 

II. ACKNOWLEDGMENTS ‘ : : ° é S 5 , 184 

III. STRATIGRAPHY : : : : é é : : 185 

(a) Middle Devonian : : A : : : : . 185 

(b) Upper Devonian . 188 

IV. GENERAL PALAEONTOLOGY OF THE Cotontaz PHILLIPSASTRAEIDAE 190 

(a) Microstructure : : : : 2 : c : 190 

(b) Increase. : : . : : : : : ; 193 

(c) Variation ¢ : 5 . : . : : : 198 

(i) Introduction . . : : : ; : : 198 

(i) Variation in diameters . : 200 

(iii) Variation in septal number acl the aaotel nates. : 203 

(iv) Variation in size ratios . : : : c é 205 

V. SySTEMATIC DESCRIPTIONS : : é : : ; 205 

Family Phillipsastraeidae C. F. Roemer c 6 : : : 208 

Genus Phillipsastrea d’Orbigny . ; : : ; 5 210 

P. hennahi hennahi (Lonsdale) . . < ‘ ‘ 214 

P. hennahi usshert subsp. nov. . : : : : 221 

P. devoniensis (Edwards & tee : F : ; 226 

P. ananas (Goldfuss) : : : : ; 228 

P. vozkowskae sp. nov. < . é . ¢ : 230 

Genus Frechastvaea nov. . : : : : 231 

F. pentagona pentagona (Goldfuss) z : 0 ; 233 

F. pentagona minima (Rézkowska) . . 5 . 236 

F. micrommata (C. F. Roemer) . 3 j : : 240 

F. carinata sp. nov. : ; : : 242 

F. goldfussi (de Verneuil & Haime) : : - é 247 

F. bowerbanki (Edwards & Haime) . ; : : 253 

Genus Thamnophyllum Penecke . : é ° c c 257 

T. germanicum gerymanicum nom. nov. 0 : 5 260 

T. gerymanicum schouppei nom. nov. . : . : 261 

T. caespitosum (Goldfuss) sensu lato . F : : 2605 

T. caespitosum paucitabulatum subsp. noy. : : 267 

Thamnophylium spp. c . c . - 5 271 

Genus Peneckiella Soshkina : : . : ; é Pazfa 

P. salternensis sp.nov. . : : : 5 : 273 

VI. REFERENCES . : ¢ . 7 : : F : 275 
SYNOPSIS 


The classification of the family Phillipsastraeidae Roemer is critically reviewed. Twelve 
species belonging to the genera Phillipsastvea, Frechastvaea gen. nov., Thamnophyllum and 
Peneckiella, and including Phillipsastrea hennahi usshert subsp. nov., P. vozkowskae sp. nov., 

GEOL, I5, 5. 21 


184 COLONIAL PHILLIPSASTRABIDAE PROM S-E. DEVON 


Frechastvaea cavinata sp. nov., Thamnophyllum caespitosum paucitabulatum subsp. nov. and 
Peneckiella salteynensis sp. nov. are described from the Middle and Upper Devonian of the 
Torquay, Paignton and Newton Abbot areas of south-east Devon. New names are proposed for 
Thamnophyllum trigeminum Penecke and Macgeea (Thamnophyllum) minima Schouppé. De- 
tailed statistical studies of variation in species and subspecies samples and individual colonies 
of many of the taxa are described and analysed. The stratigraphy of the more important 
localities from which phillipsastraeids have been collected is briefly reviewed. 


UNE ROD ie Cte ON 


Nor until the work of Schouppé (1958), over one hundred years after Lonsdale 
(1840) had erected “‘ Astrea hennahu”’, was the presence of horseshoe dissepiments 
in this, the type species of the genus Phillipsastrea generally accepted. An earlier 
record of this fact by Smith (1945 : 37), who placed very little emphasis upon it, 
appears to have passed without notice. Schouppé, however, considered dissepimental 
form and the associated trabecular structure to be of particular taxonomic importance 
in the group of Devonian rugose corals with which P/illipsastrea is associated. He 
thus attempted a thorough revision of their classification, but his suggestions are, 
in part, unacceptable where they bring together species with markedly different 
morphological characteristics, unlikely to have been closely related. 

The type locality of “ Astrea hennahiw ”’ is Barton Quarry, Torquay (south Devon) 
and many of the colonial species and genera closely related to Phillipsastvea are 
also well represented in this area. These English corals have not been examined in 
detail since the middle of the last century, when Edwards & Haime (1853) described 
them, and their taxonomic revision is long overdue. 

In the present paper the classification of the phillipsastreids is critically surveyed 
and the colonial species and genera of the Phillipsastraeidae from south-east Devon 
are described. As far as the material allows, the variation in the taxa described has 
been investigated statistically. Data collected for individual colonies of most of 
the species and subspecies enable, in addition, some comparisons to be made between 
specific and colonial variation. 

In the course of this work it has been necessary to examine a number of species 
formerly considered as phillipsastreids, but which are now removed from the 
Phillipsastraeidae. ‘These corals all belong to the family Marisastridae and have 
been described elsewhere (Scrutton 1967). 

The following abbreviations are used: BM(NH) British Museum (Natural History) ; 
OUM University Museum, Oxford; GSM Geological Survey Museum, London; 
TM Torquay Museum; TM(JB) Jukes-Browne Collection in the Torquay Museum; 
GVM Dr. G. V. Middleton’s Collection, Murchison Museum, Imperial College, London. 


II. ACKNOWLEDGMENTS 


This work formed part of a thesis submitted for the degree of D.Phil. at the 
University of Oxford. The author is indebted to both the Trustees of the Durham 
Colleges Research Studentships (Durham University) and the Burdett-Coutts 
Research Studentships (Oxford University) for financial support. 

The author is particularly grateful to Professor M. R. House (Hull) who supervised 
the work and to Professor Maria Rd6zkowska (Poznan, Poland) and to the late 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 185 


Dr. H. Dighton Thomas (British Museum (Nat. Hist.)), for invaluable discussion 
on all aspects of this paper. Acknowledgment is due to the curators of the Museums 
mentioned in the text, all of whom have been most helpful in making available 
specimens in their care. The photographs were taken by Mr. Peter Green at the 
British Museum (Nat. Hist.). Mrs. S. A. Malcolm and Mr. R. F. Wise (British 
Museum (Nat. Hist.)) have both given valuable technical assistance in the preparation 
of this paper. 

Mr. M. Mitchell (Institute of Geological Sciences, London) and Dr. G. F. Elliott 
have kindly read and criticized the palaeontological and stratigraphical sections of 
the manuscript respectively. 


Ill. STRATIGRAPHY 

A detailed account of the Devonian stratigraphy of south-east Devon is outside 
the scope of this work. As the vast majority of the material described comes from 
only six localities, however, it is intended to give a brief account of them here. 
They are confined to the limestones in the Torquay, Paignton and Newton Abbot 
areas (see Text-figs. 1, 2). Further general information on the geology of south-east 
Devon can be obtained from the Geological Survey Memoirs (Ussher 1903; Ussher 
et al. 1913; Lloyd 1933). 


(a) Middle Devonian. 

Dyer’s Quarry (SX 92206280) is situated in the coastal cliffs at the western end 
of the Daddy Hole limestone mass. Exposed to sea level in the floor of the disused 
quarry is a 15 ft. sequence of thin-bedded, black, crinoidal limestones exceedingly 
rich in coral remains, overlain by virtually unfossiliferous limestones becoming 
lighter in colour and more massive towards the top of the quarry. The total thick- 
ness of exposed rock is about 60 to 70 ft. 

The coral fauna in the floor of the quarry was mentioned briefly by Scrutton 
(1965 : 186) who suggested for it a lower Middle Givetian age. It is dominated by 
colonies of Thamnophyllum germanicum schouppei nom. nov. (see p. 120), relatively 
unbroken and apparently preserved in their position of growth. Some of the simple 
corals also appear to retain their growth orientation. This suggests a sheltered 
environment, either protected from, or situated below the effects of strong wave 
action, as the large slender branching colonies of Thamnophyllum must have been 
rather delicate structures during life. The horizon with abundant Thamnophyllum 
is sharply succeeded by dark limestones with few solitary corals. Just above the 
junction is a thin band containing rounded limestone pebbles which probably repre- 
sents contemporaneous erosion of the sea floor by wave action. 


Wolborough Quarry (SX 85237042), in the south-west outskirts of Newton 
Abbot, has produced a large and varied fauna of Middle Devonian aspect in the past 
(Whidborne 1888-1907; Ussher e¢ al. 1913 : 22-24) although corals have received 
little mention. Today, however, it is badly overgrown and the accessible outcrops 
yield only scattered fossils. The quarry is cut in massive, irregularly jointed lime- 
stones, usually coarsely crystalline, with a considerable bioclastic content and 
variously coloured from dark grey to a very pale yellowish tint. 


186 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


Phillipsastrea devomiensis (Edwards & Haime) has been recorded from Wolborough 
and Billingsastraea? battersbyi (Edwards & Haime) (see Scrutton 1967 : 277) seems 
to have been fairly common there in the past. Phillipsastrea hennahi hennahi, a 
single specimen, and Thamnophyllum caespitosum (Goldfuss) have now been collected 
from the quarry together with scattered solitary corals including Stvingophyllum sp. 

The exact stratigraphical position of the Wolborough limestone was held to be 
uncertain by Ussher et al. (1913), but House (1963 : 5) has shown that the Maenio- 


New A Cet es Gq Ove eC bal S ee 
Post Devonian | Si Say Sera ee heey oes acy : 
| 8K 2 OOS RR Da Obs 8) 252 00: Oop 
in Upper Devonian ge Bp otsorouce OR Oh rin OhaOe rhs ak Pie pene 
> a E Sie eRe ae a ta aC nan Lavi Hoy 
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[1] Middle Devonian é Soa Sok eee 
NS Recta nsec oe ae coo ee towh aarpaa AS 
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Sea Igneous rocks <a isrice sino oe Bae BGOO, 
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LLL] evenion a Cis DYER’S Q 
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ASS 7 P. ' 
Se aes re Oy i 
of, SALTERN COVE 


Fic. 1. Geological map of south-east Devon showing the main collection sites thus +. 
Inset map shows the position of the area (based on Geological Survey maps). 


ceras molarium Zone of the middle Givetian is well developed here. Middleton 
(1959) unfortunately did not describe Wolborough representatives in his paper on 
south Devon tetracorals, but later (r960, table 1) he gave a general stratigraphical 
table for the Newton Abbot area based on a modified version of Wedekind’s coral 
zones. It appears that the Wolborough limestone belongs to Middleton’s Givetian 
“biostromal and clastic limestones”’ unit, separated, at least in part, from the 
“biohermal Frasnian limestone ” of Ramsleigh Quarry and elsewhere by tuffs. 


Lummaton Hill (SX 91306645). Probably more has been written about the 
series of quarries now within the northern outskirts of Torquay, than any other 
Devonian limestone exposure in the country. An early account of the lithologies 
and faunas in the quarries was given by Jukes-Browne (1906). Despite the massive 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 187 


nature of the limestones, and the undoubted, though obscure, structural deformation, 
he suggested that a definite lithological succession could be established. Most of the 
lithological types—the massive stromatoporoid limestone, the grey shelly limestone 
of the Lummaton Shell Bed, and the bioclastic limestone of the more northern 
exposures—can still be recognized today. The rich and varied Lummaton fauna 
derives mainly from the Shell Bed and was monographed by Whidborne (1888-1907). 
The latter did not mention corals, but Jukes-Browne recorded Phillipsastrea hennaht 


STAGES TORQUAY NEWTON ABBOT 


OSTRACOD 


FAMENNIAN 
CURVISPINA SLATE 
RED SLATY 


FRASNIAN | i 

imestone with LIMESTONE 
rena |} — == = = —— 
BABBACOMBE ~ BIOHERMAL 
SLATES 


Goniatite horizon - 


+] Romsleigh Quorry 
LST. limestone 
Lummoton oe neo iad 
i nes 

TORQUAY ee 
LIMESTONE BIOSTROMAL +] Wolborough Quarry 

and limestone 
CLASTIC 
LIMESTONE 


GIVETIAN 


Dyer's Quarry limestone 


SLATE 
with fossils | 


uu 
= 
(a) 
2 
= 


DEVONIAN 


LST. 
SHALES 
with 2 | 
Calceola 
LATESEPTATUS SPILITIC | 
cultrijugatus ANDESITE 
—=S 2S MEADFOOT 
and 
WENKENBACHI STADDON 
EMSIAN BEDS 


COUVINIAN 


Fic. 2. Devonian successions for the Torquay area (modified after House & Selwood 1965) 
and the Newton Abbot area (modified after Middleton 1960). 


hennali and Haplothecia pengellyi (Edwards & Haime) from the bioclastic limestones 
in the northern end of the western quarries and noted that they did not occur else- 
where at Lummaton. Unfortunately, this particular locality has been worked out 
and these corals can no longer be collected here. They are still to be found, however, 
in limestones of a similar lithology exposed in nearby Barton Quarry. 

Recent quarrying near the supposed strike of the Shell Bed has exposed a grey 
limestone with scattered brachiopods, tabulate and simple rugose corals, bryozoa and 
broken colonies of Thamnophyllum caespitosum paucitabulatum subsp. nov. This is 
the first record of Thamnophylium from Lummaton. The lithology suggests that 
the horizon is above rather than below the Shell Bed. 

The Lummaton fauna was described by Kayser (1889 : 186) as indicative of the 
upper beds of the Middle Devonian. Recent work has fully substantiated this. 
Elliott (1961 : 256 e¢ seq.) commented on the apparent coexistence of Stvingocephalus 


188 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


burtint and “‘ Rhynchonella’’ cuboides, held to be markers for the Givetian and 
Frasnian respectively on the Continent. This had caused Ussher e¢ al. (1913 : 14) 
to consider the Lummaton limestones to be transitional across the Middle-Upper 
Devonian boundary. Elliott showed, however, that the “‘cuboides”’ from the 
Lummaton Shell Bed should be compared with the Upper Givetian Hypothyridina 
procubordes of Torley (1934) from Germany which strongly suggests a Middle Devonian 
age for this horizon. House (1963 : 6) later confirmed Elliott’s age for the Lummaton 
Shell Bed. He described a goniatite fauna from this level which can be correlated 
with the terebratum Zone of Upper Givetian age. 

Elhott (1961 : 256) quoted the occurrence of Phillipsastrea hennali hennahi at 
Lummaton and Barton as support for the presence of Frasnian rocks above the 
Givetian at both localities. Middleton (1959 : 156), however, had already recorded 
this subspecies from Middle Devonian (? upper Sparganophyllum Zone) limestones 
near Dartington Hall and it is recorded here from undoubted middle Givetian at 
Wolborough Quarry. Furthermore there is good evidence to suggest an upper 
Givetian age for the limestones at Barton from which P. hennali hennali can now 
be collected. 


Barton Quarry (SX 91246710), about a quarter of a mile north of Lummaton, 
is now used as a caravan camp. The quarry is cut in massive, mainly dark-grey 
coarse crystalline bioclastic limestone which, in the past, has yielded a large and 
varied fauna monographed by Whidborne (1888-1907) and listed by Ussher e¢ al. 
(1913 : 26). The former did not record the corals but Ussher e al. (1913 : 25) 
described finer textured parts of the limestone as abounding in corals and stromato- 
poroids. Most of the corals now seen are tabulates, mainly Thamnopora and Alveo- 
lites but it is still possible to collect a few specimens of Phillipsastrea hennahi hennahi 
and Haplothecia pengellyi together with Acanthophyllum sp. from the western wall 
of the old quarry. 

Barton is the type locality for P. hennalit. The horizon has been considered 
Frasnian in age based on early Continental records of this subspecies from Upper 
Devonian rocks. House (1963 : 6), however, has identified Wedekindella brilonense 
(Kayser) from among Whidborne’s Barton fauna, presumably coming from the 
massive limestones of the quarry. This goniatite suggests the tevebvatum Zone and 
thus an upper Givetian age. In addition Acanthophyllum has not so far been 
recorded above the Middle Devonian. Thus the evidence supports an upper Givetian 
rather than a Frasnian age for the Barton limestones and on the grounds of litholo- 
gical and faunal similarity, the beds that in the past yielded P. hennahi hennahi and 
Haplothecia pengellyi at Lummaton are probably of the same age. 


(b) Upper Devonian. 


The disused Ramsleigh Quarry (SX 84417015) is situated about a quarter of a 
mile east of East Ogwell, south-west of Newton Abbot. Exposed in the quarry 
and in the road cutting immediately to the south are massive, dominantly fine 
grained limestones, medium to pinky grey for the most part but with prominent 
lenses of a salmon pink colour. 

The age of the Ramsleigh limestones has been considered as Frasnian since the 


COLONEAE PEL rT PSA Sd RAE TD DyAVE RR OMS) 2). Di ViOIN 189 


early eighteen eighties at least. Ussher e¢ al. (913 : 15) quoted from an unpublished 
manuscript written by Champernowne in which the latter considered that the 
“splendid Ramsleigh mass... is precisely the counterpart of the marble masses of 
the ‘Etage de Frasne’ in Belgium”. A few years after Champernowne wrote 
this, Kayser (1889 : 186) correlated the Ramsleigh limestone with the Ibergerkalk 
of Germany. In more recent times, Dineley & Rhodes (1956 : 244) investigated a 
conodont fauna collected from a pale limestone band somewhat below the level in 
the quarry at which most of the massive corals are found. They concluded that the 
fauna was Lower Frasnian in age. Middleton (1959) briefly described some of the 
corals found in the quarry. Under his description of “ Phillipsastraea pentagona 
var. micrommata’”’ he wrote (p. 157) that “ According to Rézkowska this variety 
is characteristic of the upper Frasnian”’. It is presumably on this basis that he 
considered (p. 156) the Ramsleigh limestone to be “ probably middle or upper 
Frasnian”’ in age. R6ozkowska (1953), however, makes no definite statement of 
the stratigraphical range of this coral, merely describing it from the upper Frasnian 
of Poland. Furthermore, although Frechastraea carinata sp. nov. (= Phillipsastraea 
pentagona var. micrommata of authors) does occur at Ramsleigh, Middleton mis- 
identified his material which should correctly be assigned to F. pentagona minima. 
House (1963 : 6), on the evidence of ammonoids collected by Shannon from Rams- 
leigh Quarry, inferred that the lunulicosta Zone, the lowest goniatite zone in the 
Frasnian, is represented by the massive limestones. Thus the weight of the fossil 
evidence suggests that these beds are Lower Frasnian in age. 

Quite a large and varied collection of massive corals has been made from the 
quarry and the adjacent road cutting. Phillipsastrea hennahi ussheri subsp. nov., 
P. ananas (Goldfuss), P. rozkowskae sp. nov., Frechastraea pentagona pentagona 
(Goldfuss), F’. pentagona minima, F. carinata sp. nov., F. goldfussi (de Verneuil & 
Haime) and F. bowerbanki (Edwards & Haime) are described in this paper and 
Haplothecia ogwellensis Scrutton elsewhere (Scrutton 1967 : 272). Most of the 
material recently collected came from the higher parts of the old quarry face and 
from a series of outcrops in the road cutting, between 20 and 80 yards west of the 
lane leading to the quarry. 


Saltern Cove (SX 895585), on the shores of Tor Bay, is 1} miles south of Paignton. 
Resting on the altered doleritic rock, variously interpreted as a lava or a sill, which 
forms the southern horn of the cove, is a sequence of shales and limestones of Upper 
Devonian age (see Lloyd 1933 : 86 et seqg.; House 1963 : 8; Scrutton 1965 : 188). 
Immediately above the igneous rock is about 20 ft. of thick bedded limestone with 
a distinctive band rich in broken colonies of Peneckiella at the base (SX 89505842). 
This is the “‘ main Peneckiella horizon ”’ referred to elsewhere in this paper. Higher 
in the succession intercalations of red shale become increasingly important, separating 
thinner beds of limestone which completely disappear some 50 ft. above the base of 
the sequence. The corals in these thin bedded limestones have been briefly men- 
tioned by Scrutton (1965 : 188) as indicating a Frasnian age. With the presence 
of the holzapfeli Zone of Upper Frasnian age established in the northern end of the 
cove, the limestone horizons are probably within the Middle Frasnian cordatum Zone 
as inferred by House (1963 : 7-8). 


190 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


IV. GENERAL PALAEONTOLOGY OF THE COLONIAL 
PHILLIPSASTRAEIDAE 
Features of the microstructure, increase and variation in the Phillipsastraeidae 
are sufficiently uniform to warrant general treatment. By so doing much repetition 
is saved in the systematic descriptions of individual species and subspecies. The 
terminology used in this and subsequent sections is that given by Moore, Hill & 
Wells (1956) unless otherwise indicated. 


(a) Microstructure. 

Slight recrystallization or deformation of coral material may easily obscure the 
details of fine structure in the skeletal tissue. Although the preservation of the 
English Devonian material is not particularly good, all the species and subspecies 
described here do show some details of their original microstructure. 

The septa are characterized by a dark, irregular median line on either side of 
which are fibres of crystalline calcite (see for example Pl. 13, fig. 1). Where the 
preservation is best, the fibres can be seen arranged in paired tufts or fascicles on 
either side of the septal axis. Each pair is presumably the cross-section of a single 
monacanthine trabecula, with the successive centres of calcification in the fibre 
fascicles, and thus in the trabecular axes, forming the dark median line. It has not 
been possible, however, to distinguish clearly the boundaries of individual trabeculae 
in cross-section. 

The structure is most clearly developed in the dilated part of each septum, in the 
zone immediately outside the tabularium. The dilatation appears to be the result 
of simple swelling of the trabeculae. There is never more than a slight offsetting 
of the centres of calcification—in other words, very little break-up or zigzagging of 
the dark median line—to suggest that the septa become multitrabecular. 

The arrangement of the trabeculae in the vertical plane is reflected by the direction 
of divergence of the fibre fascicles from the median plane of the septum in cross- 
section (see Kato 1963, text-fig. 3). In the phillipsastraeids described here, the 
fibres can sometimes be clearly seen changing their attitude to face outwards at 
either end of the dilated part of the septum, corresponding to the fan-shaped diverg- 
ence of the trabeculae in the septal plane. The point of divergence is located more 
or less centrally in the zone of septal dilatation. 

The carination developed in Frechastraea carinata sp. nov. and Peneckiella saltern- 
ensis sp. nov. is due to the development of regularly spaced, enlarged trabeculae. 
Whilst the trabeculae retain their linear arrangement along the septal axis the carinae 
are yard-arm, but they may become offset on alternate sides of the septum, resulting 
in xyloid carination. The swollen trabeculae are sometimes separated by clear 
structureless calcite as though the trabeculae had separated and the septa become 
discontinuous. To what extent this effect is the result of recrystallization is difficult 
to ascertain. 

In longitudinal-section, the arrangement of the trabeculae in the septal plane 
can often be clearly seen (Text-figs. 3, 7b). As mentioned above, the trabeculae are 
arranged in a fan and this is centred on the crest of the dissepimentarium, usually 
formed by horseshoe or peneckielloid (R6zkowska 1960 : 32) dissepiments. In the 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 19 


zone of septal dilatation, which is most frequently sectioned in a longitudinal slice, 
the trabecular fan may often appear symmetrical about the axis of divergence. 
When more rarely a longitudinal-section is obtained of the thinner parts of the 
septum, the symmetrical arrangement is not maintained. Particularly in the species 
of Phillipsastrea and Frechastraea, the trabeculae in the dissepimentarium gradually 
return to a vertical position as the septa are traced towards the periphery of the 
corallites. In the tabularium, septa are composed of trabeculae from the edge of 
the fan, entering from the dissepimentarium at a very low angle, often almost 
horizontally. The attitude of the trabeculae appears always to be normal to the 
dissepimental surface (Text-fig. 3). 

In the case of Thamnophyllum (Text-fig. 7b), the evidence suggests that the 
trabecular fan is more nearly symmetrical in the septum although, in the major 
septa particularly, the centre of divergence is closer to the epithecal than the axial 
end. The fan in species of Peneckiella is somewhat less symmetrical and more 
variable in shape—a reflection of the diversification in dissepimental form. 


| 
si 


i 
u 
N 

| 
iN 


a 

i 
RR 
Kt 


7 
ey 


r 


V 

Ns 
ry) ay 
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ayy) 
ux) 
ani 


y 


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re 
Lar 
Ly 


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Ns 
ee) 
nyt i 
, ie 
Ki 1, 
SA SH Hirt 
Si 


203i 


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Ry 


POV TT WS 
AY 
alga 
M4 


Ad 


<a 
i] 
i 


i 
a 
itn 


. 


Fic. 3. Comparative longitudinal-sections: a. Phillipsastrea hennahi hennahi (OUM 


D520/p2); b. Frechastraea pentagona pentagona (OUM D537/p2); c. Frechastraea carinata 
(OUM D31ob). All x8. 


192 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


In the massive species described here, the septa are either more or less confluent 
between corallites (e.g. Fvechastraea bowerbankt) or intermingle to form a pseudo- 
theca. The role of individual septa is usually clear in the formation of a diffuse 
and irregular pseudotheca such as that in the astraeoid Phillipsastrea hennalu (Text- 
fig. 4c). In some species of Frechastraea, however, the peripheral ends of the septa 
are sharply geniculate and form a very strong wall by their fusion with one another 
(Text-fig. 4). The part played by the individual septa is not clear although the 
septal characteristics of the pseudotheca are obvious. In Fvechastvaea carinata, 
carinae may be rarely seen on the pseudotheca where the septal carination has been 
carried over into the wall. In the past, massive corals with such walls have been 
called cerioid (R6zkowska 1953 : 62) but this term should be strictly confined to 
massive corals in which an epitheca still surrounds individual corallites (Text-fig. 4a) 
(Lang 1923 : 123; Hill 1935 : 488). Thus the term “‘ pseudocerioid ” is introduced 
here to describe such corals as Frechastraea pentagona pentagona, F. carinata and F. 
goldfusst in which a strong pseudotheca is built up by modified septal elements. 1 


1 See Addendum. 


C Ss, ere a 
se OAR 


ARAY 
‘ A 
Bes SepsieC 
GRR oe 
ees 
BSN FRO 
SE Me 
ety OSS 
saueWa Oar Sao Ne 
OY TSR) “A 
See NCS 
ARS AS 2 oon a: 


Fic. 4. Comparative wall structures: a. cerioid—Hexagonana firthi (BM(NH) R29476); 
b. pseudocerioid—Frechastraea goldfussi (OUM D539/p2); c. weak astraeoid—Phillip- 
sastvea henna hennaht (OUM Ds520/pr). All x5. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 193 


All the massive coralla described here are presumably surrounded by a holotheca 
(Hill 1935 : 497) although it has only been observed in Fechastraea micrommata 
(C. F. Roemer) and in two sections of F. goldfussi. It is fibronormal in character 
and somewhat variable in thickness in the range 0‘I-0'I5 mm. Both the septa and 
the pseudotheca abut with a shallow convex surface against the holotheca, or penetrate 
slightly to form a wedge-shaped depression in its surface. 

Thamnophyllum germanicum schoupper, T. caespitosum, T. caespitosum paucita- 
bulatum and Peneckiella salternensis have cylindrical corallites with fibronormal 
epithecae. The peripheral septal ends meet the epitheca and depress it slightly 
(Kato 1963, text-fig. r7f) in the same manner as the relationship between septa and 
holotheca in Ff’. goldfusst. 

In all cases where the microstructure can be distinguished, the tissue of dissepi- 
ments and tabulae is fibronormal. 


(b) Increase. 


For full details of corallum increase it is necessary to cut serial sections but in the 
present material, this has been possible only with Thamnophyllum germanicum 
schouppet. Even in this subspecies, fracturing has so affected the point of branching 
that the details of septal insertion are obscured. Increase in the other taxa described 
here is known only from random sections cut through developing or immature 
individuals. Both axial and lateral increase are recorded and in some cases both 
may occur within the same colony. 

At the present time no detailed work has been done on increase in plocoid rugose 
corals. Most of the methods of increase observed in the present material, however, 
have been briefly described by Ré6zkowska (1953). The most common process is 
the development of one or more new individuals in the border area of two or more 
surrounding adult corallites (Text-figs. 5a, 6). Rozkowska (1953 : 39, 71) called 


St 
SH AD ae 


mA 
oar 
g aka: et Mi 


Fic. 5. Increase in massive Phillipsastraeidae: a. lateral (intercalicinal)—Frechastraea 
pentagona minima (GSM PF 4031); 0b. lateral—Frechastraea goldfussi (BM(NH) R46370); 
c. axial—Frechastvaea goldfussi (BM(NH) R46370). 5a x10; 5b,c x8. 


194 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


this “ intermural ” increase in the case of her “ cerioid ”’ colonies and “ intercalicinal ”’ 
increase in the forms she recognized as plocoid. In fact Rézkowska’s use of cerioid 
is equivalent to the term pseudocerioid as used here, there being no epitheca but a 
pseudotheca, formed by modified septal ends separating individual corallites: these 
colonies are also, therefore, plocoid. Intermural increase was defined by Hill 
(1935 : 491) in terms of truly cerioid coralla and it was further restricted by Jull 
(1965 : 206) to daughter corallites which appear to develop between corallite walls 
without a particular parent. In view of the literal meaning of “ intermural”’, 
Jull’s definition is accepted here as it is within the original scope of the term and is 
most suitably described by it. R6zkowska’s “intermural”’ increase (R6zkowska 
1953 : 71 did mention that the term was not altogether appropriate) is better con- 
sidered as a form of lateral increase. In some instances (Text-fig. 5d), the daughter 
corallite appears to develop in a very similar manner to that described as lateral in 
the cerioid Lithostrotion cf. portlocki by Jull (1965, text-fig. 6(z)). More usually in 
these pseudocerioid corals, however, the daughter corallite has no wall separating it 
from most, if not all, of the surrounding corallites during the early stages of develop- 
ment and the parent corallite may be very difficult to distinguish (see Rézkowska 
1953, text-fig. 35). This latter situation seems not to differ fundamentally from 
intercalicinal increase in the other plocoid corals with weak or absent corallite walls 
(for example Text-fig. 5a and Rdézkowska 1953, text-fig. 25). It is proposed, there- 
fore, to term both the intermural and intercalicinal increase of R6zkowska (1953) 
as lateral increase. Full understanding of these processes in plocoid coralla, however, 
must await studies by serial sectioning. 

Examples of axial increase have been seen much more rarely in the massive corals 
(Text-fig. 5c). Consequently, knowledge of the process is based on very few sections 
and cannot be described in full. Increase is apparently effected by the elongation 
and subsequent bilobation of the tabularium with commensurate insertion of new 
septa. The parent tabularium finally divides into two new individuals and their 
full rings of septa are completed in the area of fission. In all of the few examples 
seen there are never more than two new individuals formed at the same time. 

Axial increase has been recorded in three massive species, all of which have pre- 
dominant lateral increase (Table 1). 

The process interpreted as “ axial increase’ by R6zkowska (1953 : 65, text-fig. 
39) in her “‘ Phillipsastraea pentagona ” has also been observed in several specimens 
among the present material. From R6zkowska’s figure and a consideration of the 
English specimens, however, it is doubtful whether this is really increase but rather 
a form of rejuvenescence in massive coralla. There is no indication that this 
phenomenon ever leads to the formation of two or more individuals. Confirmation 
of this interpretation must nevertheless await evidence from serial sectioning. 

Mode of increase in the massive corals is summarized below (Table r). It is 
possible that axial increase may be shown to occur in other species than those 
indicated when more material has been examined. 

Of the phaceloid corals described here, one has exclusively axial increase and the 
others, exclusively lateral. 

Thamnophyllum caespitosum and Peneckiella salternensis have a style of increase 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 195 


TABLE 1.—Increase in massive Phillipsastraeidae. 


Lateral Axial 


Phillipsastrea 
P. hennahi hennahi >< 
P. hennahi ussheri x 
P. devoniensis No evidence 
P. ananas KH 
P. rozkowskae No evidence 
Frechastreaea 
F.. pentagona pentagona x x 
F., pentagona minima x x 
F. micrommata x 
F., carinata »< x 
F. goldfussi x x 
F. bowerbanki x 


1 After Frech, 1885, pl. 2, fig. 5. 


ce 


similar to that described as “‘ thamnophylloid lateral”? by R6dzkowska (1960 : 31). 
The daughter corallite arises from the dissepimental tissue of the parent (Text-figs. 
6, 7). In the early stages, the adult corallite becomes egg-shaped in cross-section 
with the more pointed end containing dissepimental tissue only, the septa having 
withdrawn from the epitheca in this area. This projection expands in size and septa 
begin to appear on the wall farthest from the parent. Some septa from the parent 
itself may extend slightly into the developing individual where the two are joined 
and these appear eventually to contribute to the latter’s full complement of septa. 
As the process continues, the daughter corallite grows more circular and forms a 
bilobed complex with the parent. At the same time, new septa are inserted on 


Fic. 6. Lateral increase in Peneckiella salternensis: a. OUM D553/p1; b. OUM D547/p1; 
c. OUM D547/p3 (same corallite as in 6b); d. OUM D553/pr. All x5. 


196 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


Bh 


Fic. 7. Lateral increase in Thamnophyllum caespitosum paucitabulatum: a. BM(NH) 
R46162d; b. BM(NH) R46163d. Both x3. 


both flanks of the daughter which now possesses most adult characteristics. During 
the bilobed stage, the two calices are wholly or partially separated by an irregular 
pseudotheca formed by the geniculation and mutual interference of the septa in the 
waist of the complex. The daughter corallite may be connected to the parent by 
extra-dissepimental tissue before final separation when the latter’s epitheca may 
be complete. In Thamnophyllum caespitosum two daughter corallites may be pro- 
duced at the same level but this has not been observed in Peneckiella salternensis. 
Thamnophyllum germanicum schoupper on the other hand displays exclusively 
axial increase similar to that found in many other species of Thamnophyllum. In 
all the specimens examined, either three or four daughter corallites are produced in 
each case. One specimen, in which increase is threefold, has been serial sectioned 
(Text-fig. 8). The parent corallite is about 5 mm. in diameter at the inception of 
increase which is marked by a striking change in skeletal deposition in the tabularium. 
After the last normal tabulae are laid down in the parent, the dissepimentarium 
continues to form as usual. In the tabularium, however, steeply inclined plates are 
secreted to form a cone (Text-fig. 8iii) which modifies upwards into a pyramid with 
as many sides as daughters are produced (Text-fig. 8iv, v). Upon these plates the 
new individuals are built up. As the cross-section of this axial structure changes in 
threefold increase from circular to triangular, three septa, each opposite and extending 
to join a corner of the triangle, become increasingly strongly developed. These 
delimit the areas of the new corallites. Thus each new corallite inherits roughly a 
third (or in fourfold increase, a quarter) of the mature septa and dissepiments 
of the adult. The first tabulae of each daughter are deposited between the base 
plate and the inherited dissepiments. Meanwhile the cross-section of the complex 
becomes increasingly trilobed (or tetralobed) and new septa are inserted along the 
inner margins of the developing corallites (Text-fig. 8vi, vii). The formation of the 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


a 
an 
a 


Fic. 8. Axial increase in Thamnophyllum germanicum schouppei: longitudinal-section 
after OUM D272; serial cross-sections after OUM D510/p5-10, p12-16. Spacing of 
sections in mm: i(p5)—0o-747—1ii(p6)—1-126—ili(p7)—0-712—iv(p8)—0-444—-v (po) 
0:330—vi(p10)—0-533—vii(p12)—o-208—-viii(p13)—o-267—ix(p14)—0-495—-x(p15)— 
0°574—xi(p16). All x5. 


GEOL, 15, 5. 22 


198 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


new horizontal structural elements proceeds from the periphery towards the axial 
area of the complex and by the time the process is close to completion, vertical growth 
has passed the apex of the base plates and the daughters are in intimate contact 
(Text-fig. 8vii). Subsequently, the newly formed sections of the dissepimentaria 
acquire adult characteristics with distinct traces of horseshoe dissepiments in cross- 
section (Text-fig. 8ix, x) and the new corallites complete their epithecae. Evidently 
no extra-dissepimental tissue (caenogenetic tissue of Soshkina 1953) is formed in 
Thamnophyllum germanicum schoup pet, for as soon as the normal dissepimental tissue 
is developed, the daughters become phaceloid (Text-fig. 8xi). 


(c) Variation. 


(i) Introduction. Sufficient material is available of many of the taxa described 
here to allow their variation to be studied in some detail. The statistics are grouped 
with the individual species and subspecies as part of their characterization but their 
great interest is in the general trends they show which are commented upon here. 

There are certain problems in the statistical treatment of south Devon material. 
Only one of the samples—Thamnophyllum germanmicum schoupper from Dyer’s 
Quarry—is demonstrably from a population preserved more or less in position of 
growth. In all other cases the faunas from which collections have been made have 
apparently suffered some post-mortem movement, the extent of which is difficult to 
assess. The coral colonies are broken and disorientated, in most cases preserved 
in massive limestones which have suffered more or less from tectonic stresses and 
recrystallization. 

The collections thus consist of fragmentary coralla which preclude ontogenetic 
study. The influence of ontogeny on the data obtained from these corals, however, 
appears to be small. Longitudinal-sections of corallites in the massive colonies show 
tabularium diameters to be virtually constant over most of their vertical growth. 
In this respect, they appear to behave in the same way as the phaceloid colonies, in 
which the influence of ontogeny is minimal in the extensive cylindrical parts of the 
corallites. 

All measurements have been made in cross-sections. In many colonial corals, a 
large number of corallites are unavoidably cut at varying degrees of obliquity, 
resulting in elliptical sections. As the corallites in the phaceloid colonies and the 
tabularia in all the colonial corals considered here are circular in sections normal to 
their axes, diameter measurements have been made along the minor axis of the 
ellipse. Care has been taken to separate ellipticity due to oblique section from that 
resulting from crushing or tectonic distortion. Corallites which appear to have 
been deformed in this way have not been measured. 

The following dimensions were recorded for each corallite: 


d corallite diameter. Measured only in phaceloid colonies and recorded 
to the nearest o-I mm. 

dt tabularium diameter. All of the corals described here have a 
clearly defined tabularium junction: recorded to the nearest 0°I mm. 

n number of major septa. Counts of the number of major septa were 


recorded with the corresponding d and/or dt value. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 199 


The following were calculated in the case of all massive coralla: 

A average corallite area ina colony. As it is not possible to measure 
corallite diameter in a massive colony, the average corallite area in 
a colony was measured to facilitate comparison of corallite and 
tabularium size. Values of A were obtained by counting corallite 
numbers in a cross-sectional area measured by means of a transparent 
graticule divided into squares of o-5cm. side. The number of 
corallites was then divided into the corresponding area and the result 
recorded in square centimetres. Care was taken to calculate A from 
those corallites whose tabularia were also measured. This value is 
subject to some error due to the inclusion in its calculation of some 
obliquely sectioned corallites. 

At average tabularium area in a colony. Calculated from dtx (the 
mean tabularium diameter) of each colony by the formula for the 
area of a circle and recorded in square centimetres. 

From the above basic data, the following ratios were calculated: 

dt/d tabularium, corallite diameter ratio. This ratio could only be 
calculated for phaceloid colonies. 

n/d or n/dt septal or septal-tabularium ratio respectively. The septal ratio 
as normally applied to corals is the number of major septa divided 
by the corresponding corallite diameter, which in the present work 
could only be calculated for the phaceloid colonies. In the massive 
corals, the ratio of the number of major septa to the tabularium 
diameter, called the septal-tabularium ratio, was calculated. This 
ratio behaves in a similar way to the septal ratio but is not directly 
comparable with it. It will, of course, have higher values than 
corresponding septal ratios and may vary differently with size, 
depending on the variation in the dt/d ratio. 

At/A tabularium to corallite area ratio. This ratio is the approximate 
counterpart in massive corals of the dt/d ratio in phaceloid corals. 
The At/A ratio, however, has only been calculated as an average for 
each colony and not for individual corallites because of the difficulty 
of measuring accurately the area of an irregularly polygonal corallite. 

For the dimensions and ratios mentioned above, the following standard statistics 
were calculated: 

N sample size. The number of corallites in the sample, with the number 
of colonies given in parentheses. In the case of A, At, and the 
ratio At/A, N is the number of colonies. 


O.R. overall range. 

i mean value. 

s standard deviation. 

C.V. coefficient of variation. 
S.E.m standard error of the mean. 


These elementary statistics are dealt with in many books and their application to 
zoology and palaeontology is discussed in Mayr, Linsley & Usinger (1953) and 


200 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


Simpson, Roe & Lewontin (1960). Reference has been made to both these texts 
during the present work but principally, the writer has followed Imbrie (1956). 
The latter gives a clear and concise account of all the biometric techniques used here. 
It was found necessary, however, in view of the large size of most of the samples, to 
calculate the statistics for all characters except A, At and At/A by grouping the 
data in class intervals corresponding to the o-I mm. intervals in which the diameters 
were measured. 

The statistics calculated for each species and subspecies and the representative 
colonies are given in tabular form with the systematic descriptions (Tables 4-16). 
The colonies selected for individual treatment were those in which the most corallites 
could be measured. Usually it was possible to use colonies with 50 or more corallites 
but in cases of species with large calices, smaller numbers had to be used. The colony 
with the least data is Colony 1 of Thamnophyllum germanicum schouppei with 23 
measured corallites. 

The data are also illustrated graphically (Text-figs. q-21). Inthe plots of dt against 
d, n against d or dt, n/d against d and n/dt against dt, diameter is recorded along 
the abcissa to the nearest o-I mm. As stated above, the character on the ordinate 
was averaged and plotted as a single point in each o-I mm. class. Thus points in 
the middle of the ranges of values on these graphs were based on many more observa- 
tions than those at either end. 

On all the graphs, the scatter of points approximated fairly closely to a straight 
line. When similar graphs are plotted for complete ontogenetic studies, it has been 
shown that the points usually fall on a curve of quite complicated form (see 
Voynovskiy-Kriger 1954). In the present case, however, the influence of ontogeny 
is thought to be slight and the data representative of the mature growth stages. 
Voynovskiy-Kriger’s curves approximate very closely to straight lines in maturity 
(his ‘“mature”’ plus “‘old’”’ stages), as is shown by the present results. Thus straight 
lines have been calculated from the data represented by the scatter of points on each 
graph. For ease of comparison, the lines only are illustrated in the text-figures. 
After Imbrie (1956), the reduced major axis was chosen as the most suitable line 
for problems of relative growth. 

For each line, the formula is given in the data tables as follows: 

r correlation coefficient 
a “ growth ratio ” 
b “initial growth index 

Where statistical discrimination has been used between congeneric species and 
subspecies, the procedure followed is again that detailed by Imbrie (1956). 

(ii) Variation in diameters. The assessment of size in these corals is mainly through 
the analysis of tabularium diameters as corallite diameters can only be measured in 
the phaceloid colonies. Variation in size may be the result of genetic, ontogenetic 
or ecological influences. Because of the parts played by the latter two factors, 
which are often not easy to assess, care must be taken in the significance placed on 
size differences and relative variation between colonies and species. In the present 
case, ecological control is largely an unknown factor although the influence of ontogeny 
may be regarded as minimal. 


| line of the form y = ax + b 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 201 


The variation in tabularium diameter in each of the taxa considered here is fairly 
similar (see Table 2). Values of C.V. range from 7°73 for the sample of I’vechastraea 
bowerbankz to 14°79 for the sample of Thamnophyllum germanicum schouppet. Varia- 
tion in the former, however, is almost certainly underestimated as only four incom- 
plete colonies were available for measurement. Values of C.V. for the other species 
of Frechastraea are all about ro. These figures are close to those obtained by Oliver 
(1960 : 83, table 7) for solitary cylindrical coral species and much lower than the 
variation he found in conical forms. 

From the present data it is impossible to say if massive corals are more or less 
variable than phaceloid forms. Although Thamnophyllum germanicum schouppet 
has the highest C.V. value, those for T. caespitosum paucitabulatum and Peneckiella 
salternensis are much the same as the values for many of the massive corals. In 
fact, the C.V. figure for the Barton Quarry sample of Haplothecia pengelly1, a massive 
marisastrid (see Scrutton 1967 : 274, table 2), is 15°75, which is higher than that 
for T. germanicum schoupper. On the other hand, there is a general tendency for 
C.V. values to be higher with increase in mean tabularium diameter. In the phace- 
loid corals, variation in corallite diameters is roughly the same from species to 
species, although always lower, than in the corresponding tabularium diameters. 
Oliver’s results with six solitary corals do not show such consistency and tabularium 
diameters are less variable than corallite diameters in two instances. 

Variation in size within colonies, with only two exceptions, was found to be less 
than that in the total samples of the same species or subspecies from the same locality. 
One exception is Colony 1 of Frechastraea bowerbanki (Table 12) which species has 
already been explained to be probably inadequately sampled. The other exception 
is Colony 1 of Phillipsastrea hennahi hennahi from Lummaton (Table 4). In this 
case, the C.V. value for dt in the colony only slightly exceeds that for the total 
Lummaton sample and is less than that for the sample from nearby Barton. 

There is usually a considerable range in the C.V. values for colonies of the 
same species or subspecies, even when the number of measured corallites in 
each colony is the same or nearly so. This can be illustrated with reference to 
Frechastraea goldfusst (Table 11) in which the C.V. values for ro colonies range 
from 10-01 to 4°12, the value for the total sample from Ramsleigh Quarry being 
Io-ro. 

As coral colonies are ideally the result of asexual reproduction from one sexually 
produced individual, variation would be expected to be lower in a single colony than 
in a sample of several colonies. From the results obtained here this is generally 
substantiated. The wide range in colonial variability may be due in part to several 
factors. Microenvironmental and general ecological influences undoubtedly exercise 
some control on variation but their effects cannot be easily assessed. In the case 
of phaceloid colonies, high C.V. values may be the result of the intergrowth of two 
or more colonies which have been sampled as one. As Oliver (1960 : 74) pointed out, 
it is virtually impossible to detect intergrowth when collecting material, and this 
may well have been responsible for the high C.V. values in the colonies of Thamno- 
phyllum germanicum schouppet (Table 13). Another factor for consideration is the 
fusion of several sexually produced polyps at an early stage of colony formation, 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


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COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 203 


recorded in Recent corals by Stephenson (1931 : 124). The effect of this phenomenon 
would generally be to increase the variation displayed by the colony. 

It is very difficult to separate the effects due to these different factors but it 
seems likely from the wide range in C.V. values shown, for example, by the colonies 
of F. goldfussi, that primary polyp fusion could be an important factor. 

The investigation of colonial variation described here differs from that made by 
Oliver (1960 : 73 ef seg.) through the latter comparing septal ratio C.V. values for 
individual colonies with those for populations of solitary cylindrical corals. In 
addition, Oliver analysed the total sample of Tvyplasma fascicularia from colony 
means rather than the basic corallite data. 

(iii) Variation in septal number and the septal ratios. With the exception of 
Thamnophyllum germanicum schouppe, the C.V. values for septal number are very 
similar in all the total samples. There appears to be no relationship between the 
degree of variation and the mean septal number (Table 2). 

It has long been known that septal number depends to some extent on calice size. 
When one is plotted against the other for both colonies and total samples, n shows 
a general increase with increasing d or dt in every case. Correlation coefficients in 
the total samples are usually about 0-9. The figure in individual colonies is slightly 
lower but much the same from colony to colony. Only rarely does the correlation 
coefficient drop below 0-7. These figures reflect the strength of the linear relation- 
ship between n and d or dt in mature individuals. A correlation between septal 
number and diameter is still reflected to a large extent in Table 2 as taxa with larger 
mean diameters have, with few exceptions, greater mean values for n. 

This relationship had led to the use of the septal ratio (septal coefficient of 
Voynovskiy-Kriger 1954) as a useful diagnostic criterion in coralspecies. Rdozkowska 
(1957) particularly, has used a form of this ratio, her Ms, in a detailed statistical 
study of species of Thamnophyllum and Macgeea from Poland. She showed (p. 9r 
and Table 6) that successively younger species and subspecies of Thamnophyllum 
have lower Ms values and similarly, fewer septa at a given diameter. A com- 
parison of Rozkowska’s figures with the thamnophyllids described here is shown in 
Table 3. 

It can be seen that the n values at d = 6 mm. for the English material follow the 
same trend as for the Polish specimens but do not fit exactly into the latter’s scale. 
On the other hand, the English Ms values (the English data has been recalculated 
for direct comparison with R6zkowska’s figures) are quite different from their 
approximate age equivalents in Poland and do not fit into a stratigraphical trend. 
It is interesting, however, to arrange the same taxa in order to increasing mean 
corallite diameter. This produces a series of decreasing Ms values somewhat less 
perfect than before for the Polish specimens but into which the English figures fit 
quite well. The values of n, however, show somewhat less perfect ordering than 
when arranged in stratigraphical series. 

Turning to the massive corals in Table 2, the mean n/dt figures for the representa- 
tives of Frechastraea and Phillipsastrea show a perfect series of decreasing values 
with increasing mean tabularium diameter. Furthermore, just such correlation 
exists, this time between mean d and mean n/d, in the corals described by Oliver 


204 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


TABLE 3.—Series in Ms and n (at d = 6mm.) for English (E) and Polish (P) thamnophyllids. 
Polish figures from Rdzkowska (1957 : 91 and table 6). 


Horizon Name Country Ms_ n (at 
d—6 mm.) 
8 Middle T. superius 1p 2°20 15 
a 
S 
fy Lower T. kozlowski 12 2°30 17 
Upper T. caespitosum paucitabulatum E 3°50 19°35 
a T. caespitosum caespitosum 12 3101 7/ 20 
2 (I. germanicum pajchelae) P (3:60) (21) 
2 Middle T. caespitosum E 3°15 20 
0 T. germanicum germanicum 12 3°42 Bit 
T. gerymanicum skalense 1B 3°64 22 
T. germanicum schoupper E 4°16 20°28 
xd 
4°11 T. geymanicum pajchelae 1p 3,60 21 
4°14 T. germanicum schouppei E 4°16 20°28 
5:36 T. geymanicum skalense P 3°64 22 
5:68 T. caespitosum paucitabulatum E 3:50 19°35 
(ca.) 6-00 T. caespitosum caespitosum 12 Bonz 20 
6-17 T. caespitosum E 3°15 20 
7:00 T. germanicum gerymanicum 12 3°42 21 
9°28 T. superius 12 2°20 15 
10-03 T. kozlowski 12 2°30 17 


(1960). Thus the correlation between mean size and mean septal ratio is quite 
strong. The stratigraphical series in Ms values obtained by Rézkowska may simply 
reflect the tendency in her material for larger species and subspecies of Thamno- 
phyllum to occur at higher horizons. 

Between conspecific colonies, the septal or septal-tabularium ratio behaves in the 
same way. Colonies with greater mean diameters have, with very few exceptions, 
smaller values for the mean septal ratio. 

This trend is related to the fact that the septal ratio is not constant throughout 
ontogeny but decreases in value (see Voynovskiy-Kriger 1954) with increasing 
corallite diameter. When septal ratio is plotted against diameter, the relationship 
is more or less linear for mature corallites. In the present case correlation coefficients 
for the total samples range between — 0-90 and — 0-94 for phaceloid and — 0-96 
and — 1-0 for massive corals. 

C.V. values for septal number and the septal or septal-tabularium ratio in con- 
specific colonies may show a considerable range. Furthermore, the relative variation 
in these characters and d or dt between colonies is usually different, although there 
is a slight tendency for the colony with the highest C.V. value for diameter to have 
high C.V. values for septal number and the septal ratio as well (see for example 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 205 


Table rr). In the case of n, the C.V. value reflects to some extent the rate of septal 
insertion as well as the amount of variation in diameter, and this masks any inde- 
pendent variation in the septal number. Colonies with similar variation in diameter, 
for example, show a strong correlation between a, the growth ratio, in graphs plotting 
n against d or dt and C.V. values for n. Similarly, C.V. values for n/d or n/dt in 
conspecific colonies also correlate roughly with values of a for graphs plotting n/d 
or n/dt against d or dt, and inversely with values of a for the plots of n against 
d or dt. 

(iv) Variation in size ratios. In the phaceloid forms, tabularium diameter 
increases evenly with increase in corallite diameter. The relationship between the 
two is strongly linear, reflected in the high values for the correlation coefficient 
(r > 0-95 inallcases). Only three phaceloid colonies have been analysed individually, 
those of Thamnophyllum germanicum schouppei. Their correlation lines on the graph 
plotting dt against d are virtually superimposed (Text-fig. 20). 

The ratios of tabularium to corallite diameter have very low C.V. values, partially 
reflecting the fact that they are virtually unaffected by changes in diameter. 
Measurements are confined, however, to mature corallites. Oliver (1960 : 71) has 
shown that during ontogeny in Siphonophrentis variabilis and Pseudoblothrophyllum 
helderbergium, this ratio decreases with increasing diameter. In his analyses of 
mature individuals, on the other hand, the ratio remains relatively constant with 
increasing diameter, as is shown in the present material. 

The relationship between tabularium and corallite size in massive corals is con- 
sidered in terms of their respective areas and is restricted to total samples. Analyses 
of A, At, and the At/A ratio show these characters to have high C.V. values. In 
the same sample there may be a considerable difference between the C.V. value for 
A and that for At, for example in the case of Phillipsastrea hennahi ussheri in which 
the former figure is more than double the latter (Table 5). This is undoubtedly 
due in part to the difficulty in calculating accurately the value of A. In most cases, 
however, the two figures are more nearly comparable. 

When At is plotted against A, there is always a clear tendency for the former to 
increase with increase in the latter (Text-figs. 12, 19). The scatter of points, how- 
ever, is considerable and is reflected in the low values for the correlation coefficient. 
Calculations using the formulae for the fitted lines show that the At/A ratio may 
increase or decrease slightly with increasing corallite area. Thus the analyses suggest 
that this ratio behaves similarly, if not so regularly, as the dt/d ratio and is largely 
independent of size in mature colonies. 


Vets None MAE C DESC RT Pa LO NiS 


The family name Phillipsastraeidae was erected by Roemer (1883 : 389) to include 
the genera Phillipsastrea and Pachyphyllum. It has, however, been little used until 
recently and taxonomists have usually classified the nominal type genus in the 
Disphyllidae. Hill (1939 : 224) erected the Disphyllidae to include both the typical 
Disphyllum and the related Prismatophyllum (considered by Lang, Smith & Thomas 
1940 : 104 as a junior synonym of Hexagonaria) as well as Phillipsastrea (inter- 
preted by Hill 1939 : 236 to contain species both with and without horseshoe 


206 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


dissepiments) and the exclusively horseshoe bearing genera, Thamnophyllum, Macgeea 
and Trapezophyllum. Hill’s concept of the Disphyllidae was largely influenced by 
Lang & Smith’s (1935) discussion of these genera. 

Many subsequent workers followed Hill’s combination of horseshoe and non- 
horseshoe bearing forms in the same family. Stumm (1949 : 31) extended the range 
of genera included in the Disphyllidae but divided them among three subfamilies, 
the Pachyphyllinae, Disphyllinae and Eridophyllinae, characterised respectively by 
the presence and absence of horseshoe dissepiments and the development of an 
aulos. He considered Piillipsastrea to lack horseshoe dissepiments and placed it 
with Disphyllum, Hexagonaria and Bullingsastraea in the Disphyllinae. The Pachy- 
phyllinae included Pachyphyllum, Macgeea, Thamnophyllum and Trapezophyllum. 

Soshkina (1949), on the other hand, distributed the genera and species here 
included in the Phillipsastraeidae among three new families on the basis of morpho- 
logical and ontogenetic considerations. Genera she considered to develop horseshoe 
dissepiments and a “hexacoralloid’’ microstructure—Pachyphyllum, Macgeea, 
Thamnophyllum and Synaptophyllum—Soshkina (1949 : 76) grouped in the Thamno- 
phyllidae, equivalent to Stumm’s Pachyphyllinae. She placed Phillipsastrea, 
erroneously quoting (I95I : 95) P. radiata as type species and interpreting the genus 
as lacking horseshoe dissepiments, with Neocolumnaria and Schluteria in the Neo- 
columnariidae (1949 : 145). The third new family, the Peneckiellidae (1949 : 141) 
included Peneckiella and Megaphyllum. The latter was considered by Hill 
(1956 : 280) to be a synonym of Disphyllum. 

Soshkina (1951, 1952, 1954) continued to use this classification with the introduction 
of further genera to the latter two families and (1954 : 44) replacing the name 
Neocolumnariidae by Neocampophyllidae. Spassky (1960) followed Soshkina’s 
(1954) classification. 

Wang (1950 : 217) further enlarged the Disphyllidae by incorporating the acantho- 
phyllids into the family. He based his classification on a consideration of coral 
microstructure, defining the family chiefly on the development of one or more fan 
systems in the septal trabeculae. Wang’s use of the subfamily Phacellophyllinae 
(septal trabeculae with a marked area of divergence) corresponds very closely to the 
scope of the Phillipsastraeidae as interpreted herein. Like Lang & Smith (1935) 
and Hill (1939), however, he included species both with and without horseshoe 
dissepiments in Phillipsastrea. 

Rodzkowska (1953 : 8 et seq.) considered the three different classifications of Stumm 
(1949), Wang (1950) and Soshkina (1951). She decided that coral microstructure 
was of particular diagnostic importance and for this reason followed Wang’s classi- 
fication in principle. She did, however, remove the Acanthophyllinae from the 
Disphyllidae. In addition, she used the subfamily Pachphyllinae sensw Stumm in 
preference to the Phacellophyllinae sensw Wang as the former was conceived as 
exclusive of the genus Phillipsastrea. This genus Rézkowska interpreted as lacking 
horseshoe dissepiments and placed in the subfamily Disphyllinae. 

Hill (1954a, b) reintroduced the family name Phillipsastreidae (sc) effectively as 
a senior synonym of her (1939 : 224) Disphyllidae. Although the 1954 papers 
contain no familial diagnosis, this classification was later given in full by Hull 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 207 


(1956 : 179). She considered Phillipsastrea to lack horseshoe dissepiments and thus 
placed all the genera with disphyllid and marisastrid dissepimentaria in the Phillip- 
sastraeinae, and the horseshoe bearing genera in the Phacellophyllinae. 

Schouppé (1956) discussed at length the classifications of previous authors. He 
stressed the importance of the so-called ‘“‘ hexacoralloid ” microstructure developed 
in these corals with strongly reflexed dissepimentaria, and advocated their clear 
systematic separation. Two years later, Schouppé (1958) published a classification 
on this basis, stressing at the same time the presence of horseshoe dissepiments in 
the lectotype of Phillipsastrea hennali. He placed all the genera with an area of 
divergence in their septal trabeculae, usually but not always associated with horseshoe 
dissepiments, in the Phillipsastraeacea (sic.). Thus he elevated what had previously 
been a family or even a subfamily concept to the level of a suborder. 

Schouppé subdivided the Phillipsastraeacea into the Macgeeidae, with subfamilies 
Macgeeinae and Peneckiellinae, and the Phillipsastraeidae. He placed the genera 
Phillipsastrea and Bullingsastraea together in the Phillipsastraeidae and listed 
(1958 : 233) the family characteristics as massive astraeoid form, with a pseudotheca 
and never an epitheca between adjacent corallites, and with a broad dissepimentarium 
often developing horseshoe dissepiments. Phillipsastrea and Billingsastraea, how- 
ever, are not considered to be closely related (Oliver 1964 : 2; Scrutton 1967 : 276). 
Furthermore, Schouppé placed Haplothecia Frech, Pachyphyllum sensu Rozkowska 
(x953) and Pseudoacervularia sensu Rozkowska (1953) in his synonymy for Phillip- 
sastrea, all of which include species with a partial or complete epitheca around some 
or all corallites. The Macgeeidae sensu Schouppé, on the other hand, was defined 
by the presence of horseshoe and usually also flat dissepiments in a narrow dissepi- 
mentarium, with an epitheca surrounding individual corallites. All the genera 
included in this family by Schouppé, with the exception of Synaptophyllum, belong 
to the Phillipsastraeidae as defined herein. 

R6zkowska (1957 : 82) rejected her earlier classification in favour of that proposed 
by Soshkina (1949) to the extent of placing all horseshoe dissepimentate genera in 
the Thamnophyllidae. R6zkowska referred to Schouppé’s (1956 : 151) views but 
decided to separate those forms with horseshoe dissepiments from those without 
among the group with trabecular fans. Rdzkowska (1965 : 261), however, accepted 
almost completely Schouppé’s (1958) classification and erected a new family, the 
Marisastridae, for Phillipsastraeacea with an epitheca but no horseshoe dissepiments 
(see Scrutton 1967). 

On the other hand, Strusz (1965) rejected Schouppé’s (1958) familial and ordinal 
groupings, placing all genera with horseshoe dissepiments in the Phacellophyllidae. 
Genera with trabecular fans but no horseshoe dissepiments he included in the 
Disphyllidae. Strusz (1965 : 523) drew attention to a distinction between forms 
with “half fans” and full “ disphylloid fans’ within this family but placed no 
particular taxonomic significance upon it. 

The confused classification of this group of corals reflects the difficulty of 
distinguishing clear phylogenetic relationships between the genera involved. Mor- 
phology is extremely variable, particularly in massive forms, and results in general 
gradations between the characters considered diagnostic of different family and sub- 


208 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


family groups. A particular feature of more recent classifications resulting from this 
is the uncertainty in placing corals lacking horseshoe dissepiments but having a fan 
shaped arrangement of the septal trabeculae. Schouppé (1958) grouped them with 
the horseshoe bearing forms whilst Strusz (1965) grouped them with the disphyllids 
sensu stricto. All workers are agreed, however, that horseshoe dissepiments and the 
related trabecular fans must be considered of particular importance in taxonomy. 
Horseshoe dissepiments are unique to this group of Devonian corals and great stress 
has been laid, particularly by Soshkina (1949), Schouppé (1956) and Rdzkowska 
(1957) on the development of a pseudohexacoralloid trabecular pattern. 

The trabecular arrangement alone, however, has, in the writer’s opinion, been 
somewhat overstressed and does not justify the rank of suborder sensu Schouppé 
(r958). On the other hand, the development of specialized dissepimental types 
(horseshoe and peneckielloid dissepiments), with their related trabecular structure, 
defines with relative clarity a group of corals whose general morphological character- 
istics support a close family relationship. This group includes the genus Phillip- 
sastrea (as defined herein) and should be classified as the Phillipsastraeidae. The 
writer does not agree with Strusz (1965 : 524) concerning the use of this family name. 
It must be noted that the generic name Phillipsastrea has been used far more often 
in a disphyllid sense than the corresponding family name. The genus, however, 
should not be suppressed simply because its type species has been imperfectly known 
in the past and in this case, the change in concept of the family name will naturally 
follow that of the genus. 

The genera with reflexed dissepimentaria lacking horseshoe or peneckielloid 
dissepiments but possessing an open fan shaped arrangement of the trabeculae form 
a group of their own, intermediate in character between the Phillipsastraeidae as 
defined herein and the disphyllids sensu stricto. This is formalized in the family 
Marisastridae sensu Scrutton (1967). Finally, the Disphyllidae is here restricted 
to forms in which the trabeculae are arranged in half fans, or in a sub-parallel sense 
throughout on non-reflexed dissepimentaria. This family, in the writer’s opinion, 
should be interpreted to conform strictly to the dissepimental pattern of the 
type genus Disphyllum. 


Family PHILLIPSASTRAEIDAE Roemer 1883 


1883 
partim 1922 
partim 1929 
partum 1939 
partim 1939 
partim 1939 
partim 1940 
partim 1942c 
partim 1949 
partim 1949 
partim 1949 
partim 1949 
partim 1950 
partim 1951 


Phillipsastraeidae Roemer 389. 
Campophyllidae Wedekind 3. 
Pexiphyllidae Walther 117. 
Campophyllidae; Soshkina : 12. 
Cyathophyllidae; Sanford : 408. 
Disphyllidae Hill 224. 
Disphyllidae; Hill : 258. 
Disphyllidae; Hill : 186. 
Disphyllidae; Stumm : 31. 
Thamnophyllidae Soshkina : 76. 
Peneckiellidae Soshkina : 141. 
Neocolumnariidae Soshkina : 145. 
Disphyllidae; Wang : 217. 
Disphyllidae; Taylor : 183. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 209 


partim 1952 LDisphyllidae; Lecompte : 470. 

partim 1953 Disphyllidae; Rézkowska : 9. 

partim 1954a Phillipsastreidae; Hill : 14. 

partim 1954b Phillipsastreidae; Hill : 107. 

partim 1955 Colummnariidae; Glinski : 86, 

partim 1956 Phillipsastraeidae; Hill : 279. 
1957 Thamnophyllidae; Rézkowska : 83. 

partim 1958 Macgeeidae; Schouppé : 218. 

partim 1958 Phillipsastraeidae; Schouppé : 232. 

partim 1959 Disphyllidae; Middleton : 152. 

partim 1959 Phillipsastraeidae; McLaren : 22. 

partim 1960 Thamnophyllidae; Spassky : 44. 

partim 1961 Phillipsastraeidae; Semenoff-Tian-Chansky : 294. 
1962 Thamnophyllidae; Soshkina : 308. 

partim 1962 Disphyllidae; Soshkina & Dobrolubova : 334. 

partim 1962 Phillipsastraeidae; Soshkina & Dobrolubova : 336. 
1964 Phacellophyllidae; Pedder : 366. 
1965 Phacellophyllidae; Strusz : 554. 
1966 Phacellophyllidae; Pedder : 183. 


TYPE GENUS. Phillipsastrea d’Orbigny 1849 : 12. 

Diacnosis. Solitary, dendroid, phaceloid or massive rugose corals. Septa of 
two orders, major and minor, more or less dilated at the tabularium boundary which 
is usually sharply defined. Characterized by an area of divergence in the septal 
trabeculae centred on a complete or incomplete series of horseshoe dissepiments, 
peneckielloid dissepiments or a series of highly globose dissepiments occasionally 
modified to a horseshoe form. 

DIsTRIBUTION. Lower and particularly Middle and Upper Devonian of Europe, 
Asia, Australia and North America. 


Discussion. Of the genera assigned to this family, all but two have a more or 
less well developed series of horseshoe dissepiments. The exceptions are Peneckiella 
and Frechastraea gen. nov. 

Peneckiella may show considerable variation in dissepimental form but is charac- 
terized by the development of peneckielloid dissepiments. Frequently these are 
accompanied by sigmoidal, horseshoe and flat dissepiments in varying proportions. 
R6dzkowska (1960 : 32, 48, 50) who named the Peneckiella dissepimental types con- 
sidered them to be the breakdown products of a typical Thamnophyllum dissepi- 
mentarium, and that Peneckiella evolved from this genus. 

The species and subspecies of Frechastraea develop rare horseshoe dissepiments 
against the tabularium junction. This genus is thought to have evolved from 
Phillipsastrea principally through the gradual loss of horseshoe dissepiments and 
thus should be classified with the Phillipsastraeidae. 

The full list of genera here included in the Phillipsastraeidae is as follows: 

Phillipsastrea VOrbigny 1849 (Synonyms Smithia, Pachyphyllum, Medusae- 
phyllum, ?Streptastrea, Pseudoacervularia and ? Keriophylloides). 

Macgeea Webster 1889 (Synonyms Pexiphyllum and Protomacgeea). 

Thamnophyllum Penecke 1894 (Synonym Phacellophyllum). 

Trapezophyllum Etheridge 1899. 


210 COLONDALY PHTE DLR SAS daRIASE ED PACH SERIO Sree. vaOiNi 


Peneckiella Soshkina 1939 (Synonyms Acinophyllum and Sudetia). 
Sulcorphyllum Pedder 1964. 

Bensonastraea Pedder 1966. 

Frechastraea gen. nov. (see p. 231). 


Synaptophyllum Simpson 1900 was long considered to develop horseshoe dissepi- 
ments and to belong to this group of corals. McLaren (1959), however, has shown 
that this genus had been wrongly used due to the misinterpretation of the type 
species. 

The genera fall roughly into two groups. Phillipsastrea, Sulcorphyllum, Bensonas- 
tvaea and Frechastraea usually have several rows of normal dissepiments as well as 
the modified ones, whilst Macgeea, Thamnophyllum, Peneckiella and Trapezophyllum 
commonly have only two series of dissepiments, one horseshoe or peneckielloid and 
the other usually flat. Both Schouppé (1958) and R6zkowska (1965) regarded the 
presence (in the second group) or absence of an epitheca between corallites as an 
additional criterion when they advocated a division at the family level along these 
lines. R6zkowska has particularly stressed wall structure as important in familial 
classification. 

Unfortunately, there are several exceptions to this grouping which mitigate against 
even subfamily status. Species of Phillipsastrea are known which have an epitheca 
around some corallites (Scrutton 1967 : 266) whilst a topotype of Tvapezophyllum 
elegantulum (B.M. (N.H.) R4600r) is pseudocerioid at least in part. The number of 
rows of dissepiments can be very variable in some species of Thamnophyllum (for 
example T. soshkinae (R6zkowska)) and Frechastraea (for example F. goldfussi (de 
Verneuil & Haime)). Further, a classification based on dissepimental rows would 
place Sulcorphyllum in a different group to Tvapezophyllum whereas the two genera 
appear to be closely related. Thus it is preferred not to recognize subfamily divi- 
sions in the Phillipsastraeidae. 


Genus PHILLIPSASTREA dOrbigny 1849 


1849 Phillipsastrea d’Orbigny : 12. 
partim 1850 ©Lithostrotion; d’Orbigny : 106. 
partim 1850 Favastraea; d’Orbigny : 107. 
partim 1850 <Actinocyathus; d’Orbigny : 107. 
partim 1850 Phillipsastraea; d’Orbigny : 107. 
1850 Pachyphyllum Edwards & Haime : 68. 
partim 1850 Acervularia; Edwards & Haime : 70. 
1850 Phillipsastvea; Edwards & Haime : 70. 
1851 Pachyphyllum; Edwards & Haime : 168, 396. 
partim 1851 Acervulavia; Edwards & Haime : 414 (non 171). 
parvtim 1851 Smithia Edwards & Haime : 171, 421. 
partim 1851 Syvringophyllum; Edwards & Haime : 449 (non 173). 
1851 Avachnophyllum; MCoy : 72. 
1853 Pachyphyllum; Edwards & Haime : 234. 
partim 1853 Acervularia; Edwards & Haime : 236. 
partim 1853 Smitha; Edwards & Haime : 240. 
1853 Syvingophyllum; Edwards & Haime : 242. 
partim 1855 <Acervularia; F. A. Roemer : 30. 


1855 

1855 

? 1856 
1881 
partim 1883 
partim 1883 
partim 1885 
1885 
partim 1889 
partim 1896 
1896 

1909 

1917 

1935 
partim 1935 
partim 1939 
1940 

1940 

1940 

1940 

? 1940 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


Medusaephyllum F. A. Roemer : 33. 
Smithia; F. A. Roemer : 33. 

Streptastvea Sandberger & Sandberger : 416. 
Pseudoacervularia Schiiiter : 84. 
Phillipsastraea; C. F. Roemer : 389. 
Pachyphyllum; C. F. Roemer : 392. 
Phillipsastrea; Frech : 44. 

Phillipsastvea (Pachyphylium) ; Frech : 65. 
Phillipsastraea; Schafer : 398. 
Phillipsastrea; Giirich : 178. 

Pachyphyllum; Giirich : 181. 

Smithia; Giirich : 102. 

Phillipsastvaea; Smith : 284. 

Pachyphyllum; Lang & Smith : 554. 
Phillipsastvaea; Lang & Smith : 556. 
Phillipsastvaea; Hill : 236. 

Medusaephyllum; Lang, Smith & Thomas : 83. 
Pachyphyllum; Lang, Smith & Thomas : 92. 
Phillipsastvaea; Lang, Smith & Thomas : 99. 
Pseudoacervularia; Lang, Smith & Thomas : 108, 
Streptastvaea; Lang, Smith & Thomas : 125. 


partim 1942a Phillipsastrea; Hill : 153. 
partim 1942b Phillipsastrea; Hill : 186. 
1942c Phillipsastrea; Hill : 186. 


partim 1945 
partim 1949 
1949 
partim 1950 
IQ5I 

1951 

IQ51 

Po 1O5i 
partim 1952 
partim 1952 
1953 

1953 


Phillipsastraea; Smith : 36. 
Phillipsastraea; Stumm : 34. 
Pachyphyllum; Stumm : 37. 
Phillipsastvaea; Wang : 220. 
Phillipsastvea; Taylor : 192. 
Pachyphyllum; Taylor : 193. 
Pachyphyllum; Soshkina : 84. 
Keriophylloides Soshkina : 102. 
Pachyphyllum; Soshkina : 86. 
Phillipsastraea; Lecompte : 471. 
Pachyphyllum; Rézkowska : 39. 
Pseudoacervularia; Rézkowska : 49. 


partim 1954a Phillipsastrea; Hill : 14. 
2? 1954b Phillipsastrea; Hill : 107. 


1954 
1956 
partim 1956 
1956 
partim 1958 
1958 
partim 1959 
IQ61 
partim 1962 
1964. 
1965 


But not: 
1819 
1828 
1846 


Pachyphyllum; Soshkina : 68, 

Pachyphyllum; Rézkowska : 317. 
Phillipsastvea; Hill : 280. 

Pachyphyllum; Hill : 282. 

Phillipsastvaea; Schouppé : 233. 
Pachyphyllum; Bulvanker : 89. 
Phillipsastraea; Middleton : 156. 
Pachyphyllum; Semenoff-Tian-Chansky : 303. 
Phillipsastvaea; Soshkina & Dobrolubova : 336. 
Phillipsastvaea; Fontaine : 84. 

Phillipsastvea; Strusz : 564. 


Acervularia Schweigger : tab. 6. 
Lithostrotion Fleming : 508. 
Arachnophyllum Dana : 186. 


2Ii1 


212 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


1849 Actinocyathus d’Orbigny : 12. 

1850 Syringophyllum Edwards & Haime : 72. 
1851 Phillipsastvea; Edwards & Haime : 173, 447. 
1852 Phillipsastvaea; Edwards & Haime : 203. 
1855 Syringophyllum; Edwards & Haime : 295. 
1951 Phillipsastrvaea; Soshkina : 95. 

1952 Phillipsastraea; Soshkina : 101. 

1953 Phillipsastvaea; Rézkowska : 57. 

1954 Phillipsastvaea; Soshkina : 45. 

1958 Phillipsastvaea; Bulvanker : 118. 

1960 Phillipsastvaea; Spassky : 65. 


Driacnosis. Cerioid, pseudocerioid, astraeoid, thamnasterioid, aphroid or rarely 
secondarily phaceloid, rugose corals. Major and minor septa with spindle-shaped 
dilatation at tabularium boundary. In dissepimentarium, a series of horseshoe 
dissepiments is well developed at or near junction with tabularium; several series 
of normal dissepiments also present. Tabulae complete or incomplete. 


TYPE SPECIES. (Selected by Edwards & Haime 1850: 71). Astrea hennahii 
Lonsdale (1840 : 697, pl. 58, figs. 3, 30, non fig. 3a) = Astraea hennahit Lonsdale; 
Phillips (1841 : 12, pl. 6, figs. I6«a, 16/b, 16fc, non pl. 7, fig. 15D): upper Givetian 
limestones; Barton Quarry, Torquay. 

DistripuTion. Middle and Upper Devonian of Europe and Asia. Lower and 
Middle Devonian of Australia. Upper Devonian of North America. 


Discussion. Phillipsastrea was erected by d’Orbigny (1849 : 12) who quoted as 
examples of the genus “ Astrea parallela et hennahw Phillips”. In the following 
year he redefined the genus (1850 : 107), spelling it this time Phillipsastraea and 
splitting up the specimens illustrated by Lonsdale (1840) and Phillips (1841) as 
A. hennahi among the genera Phillipsastrea, Lithostrotion and Actinocyathus. 
D’Orbigny’s original spelling Phillipsastrea is employed here following Hill (1956 : 
279) who considered the spelling Phillipsastraea to be a nomen vanum. 

The confusion created by Edwards & Haime (1850 : 70; 1851 : 173) who quoted 
first “‘ Astrea hennahia Lonsdale” and later Evismatolithus Madrepontes radiatus 
Martin (1809, pl. 18) as type species of Phillipsastrea has been clearly documented 
by Smith (1917 : 284). He showed the selection of A. hennahi to be valid and placed 
Phillipsastrea vadiata and other Carboniferous species assigned to Phillipsastrea in 
the genera Aulina and Orionastraea. 

Edwards & Haime’s invalid designation however was still accepted by Russian 
workers up to the beginning of this decade (see Soshkina 1954 : 45; Bulvanker 
1958 : 118; Spassky 1960 : 65) and Soshkina (1952 : 86) described A. hennahi 
Lonsdale as a species of Pachyphyllum. More recently, however, Soshkina & 
Dobrolubova (1962 : 336) have assigned the correct type species to Phillipsastrea. 

Various authors in the last century, particularly Edwards & Haime, assigned a 
number of Devonian colonial corals to Acervularia Schweigger. In fact, Edwards & 
Haime (1850 : 70) unwarrantably cite Acervularia roemert de Verneuil & Haime as 
type species of that genus. Acervularia, however, the type species, by monotypy, 
of which is Madrepora ananas Linnaeus 1758 : 797 = Acervularia baltica Schweigger 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 213 


1819, Table 6; Upper Silurian, Gotland, Sweden, is typically Silurian with only a 
superficial resemblance to the Devonian forms. With the closer study of internal 
structures in later years, the Devonian species of Acervularia were removed from 
that genus and usually reassigned to Phillipsastrea (see Frech 1885 : 44). Schliiter 
(r88x : 84) had, in fact, erected a new genus Pseudoacervularia expressly to cover 
the Devonian “ acervulariids ”’, but this genus has been little used. Indeed, a type 
species was not selected until Lang, Smith & Thomas (1940 : 108) chose Acervularia 
coronata Edwards & Haime for that purpose. Unfortunately the type specimens of 
A. coronata are missing but the species is almost certainly conspecific with Phillip- 
sastrea hennali, and Pseudoacervularia is a subjective synonym of Phillipsastrea. 

R6zkowska (1953 : 39), apparently unaware of Lang, Smith & Thomas’ selection, 
invalidly chose Acervularia macrommata F. A. Roemer as type species of Pseudo- 
acervularia. She described several species of that genus, all of which should be 
placed in Phillipsastrea. 

A most critical factor in the taxonomic position and interpretation of Phillipsastrea 
has been the emphasis placed by Schouppé (1958 : 156) on the development of 
horseshoe dissepiments in the lectotype of the type species. Hitherto, the presence 
of these specialized dissepiments in the lectotype had not been widely realized and 
the genus had been either restricted to species lacking horseshoe dissepiments 
(Stumm 1949 : 34; Rdzkowska 1953 : 57; Hull 1956 : 280), or considered to include 
species both with and without horseshoe dissepiments (Lang & Smith 1935 : 556; 
Hill 1939 : 236; Smith 1945 : 36). In addition, Edwards & Haime (1850 : 68) 
had erected the genus Pachyphyllum with P. bouchardi as type species. The latter 
has long been known to develop horseshoe dissepiments and many authors (Stumm 
1949 : 37; Soshkina 1951 : 84; Rozkowska 1953 : 39) have used the genus specific- 
ally for Middle and Upper Devonian massive phillipsastreids with well developed 
horseshoe dissepiments. 

Schouppé (1958 : 233 et seqg.), however, placed Pachyphyllum in synonymy with 
Phillipsastrea. At the same time, he removed all the forms previously assigned 
to the latter genus which he thought to lack horseshoe dissepiments and placed them 
in Billingsastraea Grabau (see comments under that genus by Scrutton (1967 : 276) 
and under Frechastraea gen. nov. herein). 

The writer agrees with Schouppé’s concept of Phillipsastrea with the exception of 
the placing of Haplothecia Frech. Schouppé (1958 : 201) claimed that the type species 
of the latter developed horseshoe dissepiments. However, an examination of the 
lectotype of H. filata (Schlotheim), type species of Haplothecia, does not substantiate 
this (Scrutton 1967 : 271) and the genus is here regarded as quite distinct from 
Phillipsastrea. 

Semenoff-Tian-Chansky (1961 : 303) was not convinced that Phillipsastrea and 
Pachyphyllum should be considered congeneric and he mentioned two particular 
points of apparent difference in overall size and dissepimental arrangement. With 
regard to the considerable disparity in size between the respective type species, the 
existence of species of intermediate size must not be overlooked—for example 
Phillipsastrea ananas (Goldfuss), P. devoniensis (Edwards & Haime), P. zbergensis 
(F. A. Roemer) and P. chenouwensis (Semenoff-Tian-Chansky). In fact it would 


GEOL. I5, 5. 23 


214 COLONIAL PHILLIPSASTRAETIDAE PROM S.E. DEVON 


appear that, quite fortuitously, Phillipsastrea hennahi is one of the smallest and 
Pachyphyllum bouchardi the largest of the species assigned to Phillipsastrea. The 
apparent discrepancy between Pachyphyllum and Phillipsastrea in the arrangement 
of the normal dissepiments was based on a comparison with Schouppé’s (1958, text- 
fig. 21; pl. 5, fig. r) longitudinal illustrations of P. henna. As remarked elsewhere, 
although purporting to come from the lectotype, they are completely different from 
longitudinal slides, and peels taken from that specimen by the writer, which are 
illustrated here (PI. 1, figs. 2-4, 6). There is in fact no basic difference in the dissepi- 
mental arrangement between P. hennali and P. bouchardt. 

Phullipsastrea is thus interpreted as including all those Devonian massive corals, 
excepting species of Tvapezophyllum, Sulcorphyllum and Bensonastraea, in which a 
series of horseshoe dissepiments is well developed in the dissepimentarium. Tvapezo- 
phyllum Etheridge (1899 : 32) differs from Phillipsastrea in possessing only one row 
of flat dissepiments peripheral to the horseshoe series and in this respect is related 
more closely to Thamnophyllum. Sulcorphyllum Pedder (1964 : 366) is like Tvapezo- 
phyllum but with several rows of normal dissepiments separating the peripheral flat 
dissepiments from the horseshoes adjacent to the tabularium. The irregular, 
incomplete tabulae of this genus are unlike those found in European phillipsastreids. 
Sulcorphyllum is, for the present, considered distinct from Piillipsastrea but a better 
knowledge of the variation in the former may require its taxonomic position to be 
reconsidered in the future. Bensonastraea Pedder (1966 : 183) is distinguished by 
its vepreculate and peripherally degenerate septa, and complex dissepimentarium. 


Phillipsastrea hennahi hennahi (Lonsdale) 
Plate 1, figs. -6; Plate 2, figs. 1-4 


1840 Astrea (Siderastrea) hennahit Lonsdale : 697 pars, pl. 58, figs. 3, 3b (non 3a). 
1841 Astraea hennahii Lonsdale; Phillips : 12 pars, pl. 6, figs. 16aa, 168b, 168c (non pl. 7, 
fig. 15D). 
1841 Astvaea intercellulosa Phillips : 12, pl. 6, fig. 17. 
? 1843 Astraea hennahii Lonsdale; F. A. Roemer : 5, pl. 2, fig. 13. 
1849 Phillipsastvea hennahii (Phillips) d’Orbigny : 12 pars. 
1850 Lithostrotion hennahiw (Lonsdale) d’Orbigny : 106. 
1850 Favastvaea intercellulosa (Phillips) d’Orbigny : 107. 
1850 <Actinocyathus hennahit (Phillips) d’Orbigny : 107. 
1850 Phillipsastvaea hennahvi (Phillips); d’Orbigny : 107 pars. 
P 1850 Acervularia roemeri de Verneuil & Haime : 162. 
1850 Phillipsastvea cantabrica de Verneuil & Haime : 162 (nomen nudum). 
1850 Phillipsastvea hennahi (Lonsdale); Edwards & Haime : 71 pars. 
1851 Acervularia covonata Edwards & Haime : 416. 
1851 <Acervularia voemeri de Verneuil & Haime; Edwards & Haime : 420. 
1851 Smithia hennahi (Lonsdale) Edwards & Haime : 421. 
1851 Syvingophyllume cantabricum (de Verneuil & Haime) Edwards & Haime : 451. 
1851 <Avachnophyllum hennahi (Lonsdale) M’Coy: 72. 
1853 <Acervularia coronata Edwards & Haime; Edwards & Haime: 237, pl. 53, figs. 4a—b 
(Afig. 4). 
1853 <Acervulavia voemert de Verneuil & Haime; Edwards & Haime : 239, pl. 54, figs. 3, 3a. 
1853 Smithia hennahii (Lonsdale); Edwards & Haime : 240, pl. 54, figs. 4—4d. 


~ 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 215 


1853 Syrvingophyllum cantabricum (de Verneuil & Haime); Edwards & Haime : 242, pl. 55, 
figs. 3-34. 

1855 Smithia hennahi (Phillips); F. A. Roemer : 33, pl. 6, fig. 25. 

1856 Streptastrea longivadiata Sandberger & Sandberger : 416, pl. 37, figs. 3-30. 

1879 Acervularia roemeri de Verneuil & Haime; Quenstedt : 535, pl. 162, fig. 38. 

1879 Astvea hennahii Lonsdale; Quenstedt : 535. 

1883 <Acervularia covonata Edwards & Haime; C. F. Roemer : 352. 

1883 <Acervularia roemeri de Verneuil & Haime; C. F. Roemer : 353. 

1883 Phillipsastvaea hennahii (Lonsdale); C. F. Roemer : 390. 

1885 Phillipsastrea voemevt (de Verneuil & Haime) Frech: 57 pars, pl. 4, ? fig. 2 (non 
figs. I, 3-5). 

1885 Phillipsastrvea hennahi (Lonsdale); Frech : 59 pars, pl. 5, fig. 1, (non figs. 2-4). 

1917. Phillipsastvaea hennahi (Lonsdale); Smith : 284, pl. 22, figs. 1-4. 

1945 LPhillipsastraea hennahi (Lonsdale); Smith : 37, pl. 19, figs. 1a, b. 

1952 Pachyphyllum hennahi (Lonsdale) Soshkina : 86. 

1958 Phillipsastvaea hennahi (Lonsdale); Schouppé : 235, ?text-figs. 20, 21, ?pl. 5, fig. I. 

1959 Phillipsastraea hennahi (Lonsdale); Middleton : 156. 

1963 Phillipsastvaea hennahi (Lonsdale); Fontaine : 84, pl. 8, figs. 5, 6. 


™~ 


Sey he 


™~ 


But not: 
1953 Pseudoacervularia voemeri (de Verneuil & Haime) Rézkowska: 53, text-figs. 27, 28, pl. 


7, figs. 3, 4. 


Diacnosis. Astraeoid tending to thamnasterioid Phillipsastrea. Mean tabu- 
larium diameter 2°45 mm. with ro to 16 major septa (topotype sample). Septa 
thin peripherally, with a variable spindle-shaped thickening at tabularium junction. 
Dissepimentarium composed of several rows of normal dissepiments with a single 
series of horseshoe dissepiments developed against tabularium. Tabulae complete 
or incomplete, usually in form of wide flat plates with downturned edges. Increase 
lateral. 


LeEcTOTYPE. Selected by Edwards & Haime (1851: 421). The original of 
Lonsdale’s (1840, pl. 58) figures 3 and 30 which is GSM (Geol. Soc. Coll.) 6185; upper 
Givetian limestones; Barton Quarry, Torquay. 


MATERIAL. Barton Quarry: OUM D514 (Colony 1), OUM D306 (Colony 2), 
OUM D512 (Colony 3), BM(NH) R5615 (Colony 4). Other measured specimens: 
GSM (Geol. Soc. Coll.) 6185 (lectotype), OUM D515-6, OUM D518-20, OUM D522, 
TM(JB) 107-8, TM(JB) 120. Additional material: OUM D240 (= D282), OUM 
D513, OUM D517, OUM D523, TM(JB) 1309. 

Lummaton Quarry: TM(JB) 61 (Colony 1), TM(JB) 59 (Colony 2), BM(NH) 
R23484 (Colony 3). Other measured specimens: TM(JB) 63-4, TM(JB) 78-9. 
Additional material: TM(JB) 62, TM(JB) 60. 


Wolborough Quarry: OUM Ds52rzr. 
Babbacombe Cliff: BM(NH) R46176. 
Dartington Hall: GVMr3/1, GVMr4/2. 


Torquay, South Devon: OUM D74 (holotype, Astraea intercellulosa Phillips), 
GSM (Geol. Soc. Coll.) 618g (lectotype here chosen, Syvingophyllum cantabricum 
Edwards & Haime). 


216 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


DISTRIBUTION. England: upper Givetian limestones of Barton and Lummaton 
quarries, Torquay; middle Givetian limestones of Wolborough Quarry, Newton 
Abbot; Givetian limestones, 100 ft. above sea level, south end Babbacombe cliffs, 
Torquay; middle Givetian limestones of Dartington Hall area (Middleton 1959); 
Middle Devonian, Plymouth (Phillips 1841). Devonian, Kikai, Yunnan (Fontaine 
1963). Also represented in the Frasnian, Ibergerkalk, Bad Grund, Harz, Germany 
(Frech 1885). Middle Devonian, Pola de Gordon, Léon, Spain (de Verneuil 
& Haime 1850). 

DEscRIPTION. All specimens are incomplete and details of the colony exterior, 
its overall size and shape are unknown. The largest specimen examined was, when 
complete, 17 < 14 cm. in surface area and 5 cm. deep (it isnow in two pieces numbered 
separately as OUM D240 and OUM D282). 

Colonies are astraeoid tending to thamnasterioid, with a straight or zigzagged 
pseudotheca of variable strength separating the corallites. This pseudotheca may 
break down round parts of the corallite margins when the septa run more or less 
confluently from one corallite to the next. 

The septa, major and minor, are very thin peripherally, less than o-I mm. and 
normally about 0:025mm. in thickness. They may have smooth or slightly 
roughened sides and rarely some separation of the trabeculae but they are never 
truly carinate. They are usually sinuous, seldom straight, in the dissepimentarium 
and occasionally curved in a constant direction to form a vortex. The septa develop 
a spindle-shaped dilatation in the region of the tabularium junction. It is extremely 
variable both within colonies and individual corallites, ranging normally between 
o-15 and 0-25 mm. width and 1 to 2 mm. length (see, for example TM(JB)79, Pl. 2, 
fig. 1). 

Within the tabularium, the major septa usually taper smoothly and end somewhat 
short of the axis of the corallite. Occasionally, however, some may reach the axis, 
or cross the tabularium periaxially to join with major septa in the adjacent quadrant 
of the corallite. Rarely the axial ends of the major septa may develop slight lobate 
thickenings. The minor septa do not enter the tabularium. 

Dissepiments are usually uniserial but may occasionally be multiserial between 
adjacent septa. In cross-section they are well spaced peripherally, becoming more 
crowded towards the tabularium junction which is sharply defined. Against this 
junction, the trace of a single series of horseshoe dissepiments is sometimes clearly 
seen (Pl. 2, fig. 2 corallite in right centre). 

In longitudinal-section, the dissepimentarium is composed of several rows of 
small, normal dissepiments, between 0-2 and 0-5 mm. in height. They are weakly 
arched peripherally but become increasingly globose towards the tabularium 
boundary. The dissepiments immediately adjacent to the tabularium are modified 
into horseshoe form resulting in a single vertical series of more or less well developed 
horseshoe dissepiments (Pl. 1, figs. 2-6). The surface of the dissepimentarium slopes 
downwards away from this series and flattens out peripherally. 

The tabulae are complete or incomplete, more usually the latter. In general they 
are strikingly flat and parallel across the axis of the tabularium, usually with down- 
turned peripheral edges. There is a limited development of vesicular, periaxial 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


90 


80 


70 


60 


50 


40 


30 


20 


Total sample 


1 
1-45 1:85 2:25 2-65 3:05 3-45 


dt (0-2mm class intervals) 


1-6 2-0 2-4 
dt (mm) 
Colony 1 Colony 2 Colony 3 


Fic. 9. Phillipsastvea hennahi hennahi (Barton sample). 


2:8 


3:2 


Colony 4 


PNG 


3:6 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


218 


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‘(gjdures uoyemuiny) wyvuuey wouuay vaysvsdyjwd jo sioyoereyo 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 219 


110 


100 


90 


80 


70 


60 


50 


40 


30 


20 


f 
4 


LE Wy SN e 
(0) ; fos wee i 1 I Ree as \ 


1:45 185 2-25 2:65 3:05 
dt (0:2 mm class intervals) 


1:6 2:0 2-4 2:8 
dt (mm) 


Total sample Colony 1 Colony 2 Colony 3 


Fic. 10. Phillipsastrea hennahi hennahi (Lummaton sample). 


220 COLONIAL PHILP TR SAS Di AL DD A se ROMS Se. Divi OIN| 


elements. Tabularium structure varies in complexity from the simple, interleaved 
tabulae of TM(JB) 79 (PI. 1, fig. 5) to the close spaced series of flat-topped domes in 
GSM (Geol. Soc. Coll.) 6185 (Pl. 1, figs. 2-4, 6). 

Despite the large number of specimens examined, only one instance of lateral 
increase has been seen and that is in the lectotype. 

Statistical analyses have been made of samples of this subspecies from the type 
locality, Barton Quarry (14 colonies) and Lummaton Quarry (7 colonies), both in 
Torquay. Four colonies from Barton and three from Lummaton have been analysed 
individually. The statistics are given in Table 4 and illustrated graphically in 
Text-figs. 9, 0 and 12. 

The topotypes are characterized by a mean tabularium diameter of 2:45 mm. with 
ro to 16 major septa and a mean septal-tabularium ratio of 5:25. The Lummaton 
specimens differ principally in having a smaller overall range and mean dt, and a 
somewhat larger mean n/dt. 

Colonial variation at the two localities displays an interesting contrast. Generally 
there is a greater range in the mean values of the quantitative characters between 
the colonies from Barton, although variation within each colony is much the same. 
The Lummaton colonies, on the other hand, have very similar mean values but 
markedly different degrees of variation from colony to colony. 


Discussion. The specimen on which Phillips (1841 : 12) erected Astvaea tmter- 
cellulosa is OUM D74 (PI. 2, figs. 2, 3). Phillips himself had great doubts as to 
whether or not his specimen was distinct from Lonsdale’s species. In the writer’s 
opinion it is an atypical representative of P. hennaht hennahi in which the septa are 
virtually unthickened. 

F. A. Roemer (1843 : 5, pl. 2, fig. 13) described and figured as Astvaea hennalt 
Lonsdale a specimen which was later selected by de Verneuil & Haime (1850 : 162) 
as the type of a new species Acervularia voemert. The identity of Roemer’s original 
is uncertain but Edwards & Haime (1853 : 239, pl. 54, figs. 3, 3a) later recorded A. 
voemert from Torquay. The latter’s specimen, judging from their figures, is almost 
certainly consubspecific with P. hennahi hennaht. Frech (1885, pl. 4, figs. I-5) also 
figured Phillipsastrea roemert (de Verneuil & Haime), of which, if his interpretation 
was correct, the original of his fig. 2 is a topotype. Again it appears from the 
illustration that the specimen may be consubspecific with Phillipsastrea hennaht 
hennahi. 

Edwards & Haime (1853) described and figured two species, Acervularia coronata 
and Syringophyllum cantabricum, previously erected by them in 1851 (p. 416 and 
p. 451 respectively). In the case of A. coronata, Edwards & Haime’s original material 
has been lost or mislaid. From their illustrations (1853, pl. 53, figs. 4a, 0) of a 
specimen from Barton, however, the species is almost certainly the same as the 
present subspecies. ‘‘ Phillipsastvea cantabrica n. sp.” in de Verneuil & Haime 
(1850 : 162) is a momen nudum as they give neither description nor figures of the species. 
Edward & Haime (1851 : 451) must therefore be regarded as the authors of the 
species with their description of “ Syringophyllum? cantabricum (de Verneuil & 
Haime)”’. The original of Edwards & Haime’s (1853, pl. 55, figs. 3, 3a) figures of 
Syringophyllum cantabricum is specimen GSM (Geol. Soc. Coll.) 6189, which is here 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 221 


chosen as lectotype of the species (Pl. 2, fig. 4). This specimen is consubspecific 
with P. hennali hennahi. 

Schouppé (1958, text-fig. 21, pl. 5, fig. 1) published two illustrations which he 
stated were taken from a longitudinal peel of specimen GSM (Geol. Soc. Coll.) 6185. 
The structure of both the tabularium and the dissepimentarium in Schouppé’s 
figures, however, is not that seen in this specimen although the presence of horseshoe 
dissepiments can be confirmed. The source of Schouppé’s figures must thus be 
considered somewhat enigmatic. 


Phillipsastrea hennahi ussheri subsp. nov. 


Plate 3, figs. I-3 

DERIVATION OF NAME. The subspecies is named after W. A. E. Ussher (1849- 
1920). 

Dracnosis. Astraeoid tending to thamnasterioid Pillipsastrea. Mean tabular- 
ium diameter 2:04 mm. with ro to 14 major septa (topotype sample). Septa thin 
peripherally but usually strongly dilated at tabularium junction, becoming laterally 
contiguous and forming a dense inner wall. Horseshoe dissepiments developed in 
a series adjacent to tabularium with several rows of normal dissepiments peripherally. 
Tabulae usually incomplete with narrow axial series of flat topped domes irregularly 
developed. Increase lateral. 


HototyPeE. OUM D544. Lower Frasnian limestones; road cutting, 20 yd. west 
of the entrance to Ramsleigh Quarry, East Ogwell, near Newton Abbot. 


MATERIAL. Ramsleigh Quarry: BM(NH) R23402 (Colony 1), BM(NH) R5616 
(Colony 2), BM(NH) R23209 (Colony 3). 

Road cutting, 40 yd. west of Ramsleigh Quarry entrance. Measured specimens: 
OUM D533-4. 


Road cutting, 20 yd. west of Ramsleigh Quarry entrance. OUM D545. 
DISTRIBUTION. Lower Frasnian limestones in and around Ramsleigh Quarry. 


DESCRIPTION. Only incomplete colonies have been found and the overall colony 
shape, size and external features are unknown. 

The colonies are astraeoid tending to thamnasterioid with considerable variation 
in the strength of the pseudotheca. Perfectly confluent septa between adjacent 
corallites, however, are rare. Septa are thin peripherally, usually about 0-06 mm. 
thick, occasionally straight but more usually sinuous. The sides of the septa may 
be smooth or slightly crenulate; carinae are not developed. Immediately adjacent 
to the tabularium, the septa are dilated. The short, spindle-shaped thickening is 
greater on the major septa when it is usually 0-5 to 0-7 mm. long and about 0°25 mm. 
wide. The dilatation is a very constant feature, frequently bringing adjacent 
septa into contact to form a dense wall, about 0-5 mm. wide, round the tabularium. 
Minor septa end at the tabularium junction but the major septa thin abruptly and 
continue as very fine filaments, about 0-02 mm. thick, towards the axis of the corallite. 
Sometimes the ends of the major septa, slightly withdrawn from the axis, bear small 
lobate thickenings which through lateral contact may form a pseudoaulos. In 


222 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


70 


60 


40 


30 


1:05 1:45 1:85 2:25 2-65 
dt (0-2 mm class intervals) 


Total sample Colony 1 Colony 2 Colony 3 


Fic. 11. Phillipsastvea hennahi ussher. 


COLONIAL PHILLIPSASTRAEIDAE PROM S.E. DEVON 223 


TABLE 5.—Statistical data for some characters of Phillipsastvea hennahi ussheri. 


Total 
sample Colony 1 Colony 2. Colony 3 


N 169 (5) 60 48 46 
O.R. I*2-2'5 I+2-2°2 I°6-2°5 2°I-2'5 
x 2:04 I-QI 2°03 2°27 
dt Ss 0-22 0-18 0-16 0-094 
G.vV. 10-61 9°47 8-oO1 4°14 
S.E.n 0:O017 0:023 0:024 0-014 
O.R. 10-14 10-14 II-I4 II-I4 
xX 12°46 12:37 12°50 12:78 
n S 0:38 0°39 0°37 0-48 
C.V. 3°07 Bais 2°97 3°79 
S.E.n 0:029 0-051 0:054 0-071 


O.R. 4:70-9:16 5:71-9:16 5:20-8:12 5:00-6-19 


x 6-16 6°55 6°18 5°63 
n/dt s 0°55 0°55 0°41 0-052 
C.V. 8-97 8-37 6:62 0-92 
S.E.n 0:043 0-071 0:059 0:0077 
Graphs :— 
r 93 0-92 0-72 0:98 
n/dt a 7/7) AO) 2:28 5°15 
b 8-86 8-23 7-86 1:09 
n/dt r —0-96 —o-96 —o:gI —o-46 
a —2:56 — 3°04 —2°52 —0°55 
dt b 11-38 12°33 II-30 6:89 
A At At/A Graph:—At/A 
O.R. 0°36-0°89 0:026-0-04I 0:037—0-:081 r 0°32 
x 0°55 0-032 0-063 a 0-027 
s 0-21 0-0055 0-017 b 0-018 
G.vV. 37°69 17°09 26:12 
S.E.n 0-092 0:0025 00-0061 


other cases, the septal ends are free, or fused in groups of two or three in the centre 
of the tabularium. 

Usually the dissepiments are uniserial between adjacent septa and appear rather 
closely spaced in cross-section. Around the tabularium, and coincidental with the 
septal thickening, the traces of a single series of horseshoe dissepiments form two 


224 COLONIAL PHILEIPSAST RABEL DAE BROOM sph. DEVON 


strong concentric walls (Pl. 3, fig. 1), or delimit the width of the single thick wall 
when the septa are in lateral contact (PI. 3, fig. 3). 

In longitudinal-section, the dissepimentarium is composed of several rows of 
small, globose dissepiments, usually between o-r and 0-3 mm. in height. Immedi- 
ately adjacent to the tabularium, the dissepiments are quite sharply modified into 
a vertical series of horseshoes, predominantly uniserial and quite regularly developed. 
The surface of the dissepimentarium slopes steeply away from the series of horseshoe 
dissepiments but is flat over most of its area. The tabularium junction is sharply 
defined. 

Tabularium structure is not perfectly clear from the present material. The 
tabulae appear to be closely spaced and usually incomplete. Often there is a wide 
peripheral series of horizontal plates, slightly distally concave, abutting against a 
central series of small, flat-topped or occasionally globular domes, which occupy a 
third to a quarter of the tabularium diameter. In other portions of the tabularium, 
this axial structure is missing and the whole width is occupied by flat, interleaved 
plates. 

Four examples of lateral increase have been seen in BM (NH) R56r16 although in 
each case the new individuals are well advanced. 

A small sample of five colonies of this subspecies has been statistically analysed. 
Three of the colonies have also been treated separately to investigate colonial 
variation. The resulting statistics are given in Table 5 and the data illustrated 
graphically in Text-figs. rm and 12. 


Discussion. It is possible that some of the material from Upper Devonian 
localities in continental Europe which has been described as Phillipsastvea hennahi 
properly belongs to this subspecies; for example, the specimen figured by Frech 
(1885, pl. 5, fig. 2) from the Frasnian Ibergerkalk at Bad Grund, Germany. 


Comparison of the subspecies of Phillipsastrea henna. The main quantitative 
characteristics of P. hennali hennai (Barton Quarry sample) and P. hennahi usshert 
have been statistically compared and the results are tabulated below: 


dt t = 14°69 (524° freedom) P <o-or 
n/dt z (slope) = 7°38 P <o-or 

Zi (Slope) — ior P= 0-08 
aes Z (position) = 7:02 P <o-or 


The mean tabularium diameter for P. hennahi usshert (2-04 mm.) is significantly 
smaller than that for P. hennahi hennahi (2:45 mm.). There is also a significant 
difference between the slopes of the correlation lines on the graph plotting n against 
dt for the two subspecies. The number of major septa increases slightly faster with 
increasing tabularium diameter in the Frasnian subspecies. The number of points 
on the graph plotting At against A is rather low to allow the results of a “z”’ test 
to be uncritically accepted (Imbrie 1956 : 237, footnote r). Nevertheless, the signi- 
ficant difference in position reflects the small degree of overlap of the points for the 
two subspecies. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


100 


80 


60 


40 


20 


At 


(sq. cms) 


J v \ c om~< 
4 \ . 
cA \ NS \ 
eS: Ne 
1 1 1 Pn I 
1:85 2°25 2:65 3-05 


1-2 16 2:0 24 2:8 
dt (mm) 
Phillipsastrea hennahi hennahi 


Phillipsastrea 
Fic. 12. 


hennahi 


(0:2 mm class intervals) 


3:2 3-6 


(x) Barton 


ussheri 


Phillipsastrvea hennahi. 


(0) Lummaton 


(*) East Ogwell 


Graphical comparison of some quantitative characters for the subspecies of 


226 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


Qualitatively the two subspecies are very similar and obviously closely related. 
The strong cross-sectional traces of horseshoe dissepiments, usually infilled by close 
packed septal tissue, which surrounds the tabularium in P. hennahi ussheri is, 
however, very distinctive. The horseshoe traces are rarely so clearly seen in P. 
hennali hennalu and excessive septal dilatation is similarly uncommon. The major 
septa within the tabularium are also contrasted in the two subspecies. The abrupt 
attenuation of the septa, which closely approach the axis, often with a lobate thicken- 
ing of their axial ends, is characteristic of P. hennahi usshert. The major septa of 
P. henna hennahi are usually somewhat withdrawn from the axis and taper away 
from the dilated zone. 

In longitudinal-section, the most noticeable difference between the two subspecies 
is in the tabularium structure. The narrow axial domes and wide, flat peripheral 
plates of P. hennahi usshert contrast with the broad based, flat-topped domes of 
P. hennahi hennaht. There is, however, no characteristic difference between the 
dissepimentaria of the two subspecies. 


Phillipsastrea devoniensis (Edwards & Haime) 
Plate 4, figs. I-4 


1851 Pachyphyllum devoniense Edwards & Haime : 397. 

1853 Pachyphyllum devoniense Edwards & Haime; Edwards & Haime : 234, pl. 52, figs. 5, 5a. 
1883 Pachyphyllum devoniense Edwards & Haime; C. F. Roemer : 393, text-fig. 93. 

1885 Phillipsastrea (Pachyphyllum) devomense (Edwards & Haime) Frech : 67, pl. 6, figs. 2, 2a. 
1952 Pachyphyllum devoniense Edwards & Haime; Soshkina : 86. 


But not: 
1958 Pachyphyllum devoniense Edwards & Haime; Bulvanker : 93, pl. 45, figs. 1a, b. 


Dracnosis. Astraeoid tending to thamnasterioid P/illipsastrea with poorly 
defined corallite margins. Mean tabularium diameter 3°72 mm. with 16 to 23 
major septa (South Devon sample). Septa generally thin, with slight, elongate 
dilatation surrounding tabularium. In longitudinal-section, a series of horseshoe 
dissepiments is developed just outside tabularium junction. Tabulae wide, flat, 
complete or incomplete. 


Hototyre. The original of Edwards & Haime’s (1853, pl. 52) fig. 5 and 5a; 
Devonian, Torquay. This specimen is either mislaid or lost. 

MATERIAL. “‘ Rocky Valley”. Measured specimens: OUM D277, BM(NH) 
74489. 

?Lummaton Quarry. Measured specimen: TM(JB) 105. 

Torquay, S. Devon: BM(NH) Rr456. 


DISTRIBUTION. England: 7m situ only from middle Givetian limestones, Wol- 
borough Quarry, Newton Abbot and ?from upper Givetian limestones, Lummaton 
Quarry, Torquay. Other specimens are beach pebbles, several being known from 
“Rocky Valley” (? = Valley of Rocks, Watcombe, north of Torquay). Also 
recorded from the Ibergerkalk, Bad Grund, Germany; Frasnian. 


COLONTAL PHILETPSASTRAEIDAE PROM S.E. DEVON 227 


DeEscrRIPTION. Nothing is known of the overall size, shape and external features 
of this species. 

Colonies are astraeoid tending to thamnasterioid. The septa are usually out- 
wardly geniculate and irregularly abutting. Occasionally they may be perfectly 
confluent from one corallite to the next or rarely they end in the dissepimentarium 
with a free peripheral end. The margins of the corallites are indistinctly defined in 
the absence of a well formed pseudotheca. 

The septa, major and minor, are 0-I mm. or less in thickness in the dissepimentarium 
where they follow a straight or sinuous course. Ina zone surrounding the tabularium 
of r to I-5 mm. width, the septa have a slight, elongate dilatation, usually to about 
0-2 or 0-3 mm. thickness. Minor septa project just within the tabularium. The 
major septa continue in a strongly attenuate form more or less to the axis, where 
their ends may be free and infrequently slightly thickened, or confluent with septa 
in the adjacent quadrant of the tabularium. Carinae are not developed. 

Dissepiments are usually uniserial between adjacent septa. Just outside the 
tabularium, in the zone of septal dilatation, cross-sectional traces of horseshoe 
dissepiments are often clearly visible. The tabularium junction is clearly defined. 

In longitudinal-section, the dissepimentarium is composed of several series of 
arched dissepiments usually between 0-2 and 0-4mm. high. Just outside the 
tabularium, a slightly discontinuous single series of irregularly sized horseshoe 
dissepiments is developed. From the crest of the series, the dissepiments slope 
steeply downwards towards the corallite margins where they become flat lying. 
On the axial side of the horseshoes, one or two rows of normal dissepiments are 
usually present. 

The tabularium, which is more or less sharply delimited from the dissepimentarium, 
is composed of wide, flat or gently undulating plates, usually slightly downturned 
peripherally. The tabulae are complete or incomplete and a periaxial series of 
sloping plates is intermittently developed. 

Insufficient material is available for a statistical study of variation in this species. 
The few measurements made are summarized in Table 6. 


Discussion. The present material agrees very well with Edwards & Haime’s 
(1853 : 234, pl. 52, figs. 5, 5a) figures and descriptions, although their original speci- 
men appears to have had somewhat larger tabularia. Frech’s (1885) figures of a 
specimen from the Ibergerkalk (Harz, Germany) are very close to the illustrations of 
the holotype and to the present material, although the horseshoe dissepiments in the 
German specimen appear stronger and more regularly developed. 

Phillipsastrea devoniensis differs markedly from P. hennadi in both tabularium 
size and septal number. In addition, the horseshoe dissepiments of the former are 
somewhat less regular in size and, unlike those of P. hennali, are separated from the 
tabularium by steep sloping normal dissepiments. The thin elongate septal dilata- 
tion in P. devoniensis (Pl. 4, fig. 2) also contrasts with the markedly spindle-shaped 
septa of P. hennahi (Pl. t, fig. 1). 

P. devoniensis is similar in many respects to P. bouchardi and P. ibergensis. Both 
the latter species, however, have slightly different tabularium structure and P. 
bouchard: has much larger tabularia (dt = 10-16 mm. according to Semenoff-Tian- 


228 COLONTAL PHILETPRS ASTRA DDS EROS =) Di VOI 


Chansky 1961 : 307) than P. devoniensis. P. ibergensis is further distinguished by 
strong spindle shaped septal dilatation. 

The specimen figured by Bulvanker (1958, pl. 45, figs. 1a, 6) as P. devoniense has 
considerably larger tabularia than the English material. It is closer in size to P. 
bouchardi and also has the slightly sagging tabularium structure of that species in 
contrast to the flat or faintly domed tabulae of P. devoniensis. 

P. devoniensis is an uncommon species. Very few specimens have been seen in 
English museums and the author has found none in the field. It appears that 
Frech’s (1885 : 67) specimen is the only record of the species from abroad. 


Phillipsastrea ananas (Goldfuss) 
Plate 5, figs. 1-4 


1826 Cyathophyllum ananas Goldfuss : 60 pars, pl. 10, fig. 4b, non 4a. 

1851 <Acervularia troscheh Edwards & Haime : 416. 

1885 Phillipsastvea ananas (Goldfuss) Frech : 49 pars, pl. 2, figs. I, 2, 5, 5a, 5b, pl. 3, ?fig. 5; 
pl. 8, ?fig. 9. 

1953 -Pseudoacervulavia ananas (Goldfuss) Rézkowska : 52, text-figs. 27, 28, pl. 7, figs. 1, 2. 


But not: 
1881 Heliophyllum troscheli (Edwards & Haime); Schliiter : 203, pl. 4, figs. 3, 4. 


Diacnosis. Pseudocerioid Phillipsastrea. Mean tabularium diameter 3:54 mm. 
with 14-18 major septa (East Ogwell sample). Septa thin peripherally, with slim, 
spindle-shaped dilatation near tabularium boundary. Major septa usually form 
weak axial vortex. Dissepimentarium reflexed, with imperfect series of horseshoe 
dissepiments at crest from which two or three rows of normal dissepiments slope 
steeply into tabularium. Axial tabulae flat-topped domes with peripheral horizontal 
concave plates. 


TYPE SPECIMEN. The original specimen figured by Goldfuss (1826, pl. 19, fig. 4b) 
is either mislaid or lost. Frasnian; Namur, Belgium. 


MATERIAL. BM (N.H.) R46158-9. Road cutting, south side, 30-35 yd. west of 
Ramsleigh Quarry entrance, East Ogwell, near Newton Abbot; Lower Frasnian. 


DISTRIBUTION. England: Lower Frasnian; East Ogwell, near Newton Abbot. 
Also widespread in Frasnian of Namur, Belgium; Harz, Stolberg near Aachen, 
Germany; Kielce region, Poland; Urals, Kuznetsk Basin, U.S.S.R. 


DESCRIPTION. The material consists of fragments of apparently pseudocerioid 
coralla. The epitheca is predominantly straight but may be zigzagged. 

The septa, both major and minor, are spindle-shaped. At the periphery they 
are about 0-05 mm. across but the major septa may dilate up to 0-45 mm. thick near 
the tabularium junction. The maximum length of septal thickening is about 2 mm. 
The septa may be carinate. BM (N.H.) R46159 (PI. 5, fig. 3) has well developed 
yardarm carinae, up to 0:25 mm. across with a minimum spacing of 0-I5 mm., on 
many but not allsepta. BM (N.H.) R46158 (PI. 5, fig. 2) on the other hand has only 
rarely developed, very faint, carinae. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 229 


The minor septa do not penetrate the tabularium but the major septa continue, 
much attenuated, almost to the axis where they usually form a weak vortex. There 
is usually an axial area 0-2—0-4 mm. in diameter which is free of septa. 

The dissepiments may be uni- or multiserial between septa. The tabularium 
junction is not strongly marked but coincides approximately with the axial ends of 
the minor septa. 


TABLE 6.—Quantitative comparison of some species and subspecies of Phillipsastrea. 


dt n n/dt At/A 
(aia Lae ae 
O.R. X O.R. xX Xe 
P. hennahi hennahi 1°7-3°5 2°45 10-16 5°25 0°045 
P. hennahi ussheri I+2-2°5 2°04 IO-I4 6:16 0:063 
P. devoniensis 3:0-5:0 3°72 16-23 5:04 Cca.O'r 
P. ananas 3°0-4°0 3°54 14-18 4°44 Ca.O°15 
P. vozkowskae 2°3-2'9 2:64 12-15 5°08 ca.o-I 


In longitudinal-section, the dissepimentarium is of variable width, and the dissepi- 
mental surface strongly reflexed with the crest on average 0-6 mm. outside the 
tabularium. The dissepiments at the crest are usually modified to horseshoe shape, 
forming a slightly discontinuous vertical series of horseshoe dissepiments. There 
are several rows of normal dissepiments towards the margins of the corallites and 
on the other side of the crest, two or three rows of dissepiments slope steeply into the 
tabularium. 

The tabulae are complete or incomplete flat-topped domes, occupying about 
three-fifths of the tabularium diameter. There is a peripheral series of horizontal, 
distally concave plates. 

The two known specimens from East Ogwell have slightly different quantitative 
data which is averaged in Table 6. Individually, BM (N.H.) R46159 has tabu- 
larium diameters of 3 to 3°5 mm. with 14 or 15 major septa whilst BM (N.H.) R46158 
has 3°8 to 4:0 mm. tabularium diameters with 15 to 18 major septa. 


Discussion. Although the two specimens described here differ slightly in some 
respects, they both appear to fall within the range of variation shown by P. ananas 
in areas where the species is more abundant. On the other hand, they also show 
some features which are intermediate in character with P. macrommata (F. A. Roemer). 

Frech (1885 : 49) considered these two species to be synonymous whilst R6zkowska 
(1953 : 49-52) was able to distinguish between them in Poland through the lower 
septal-tabularium ratio, the short, strong septal dilatation and the slightly different 
dissepimental arrangement in P. macrommata. The English material agrees in 
general morphological appearance with P. ananas of R6dzkowska. On the other 
hand, the septal insertion in both the present specimens follows more closely the 
curve for P. macrommata given by Rézkowska (1957, text-fig. 26). 

In view of the limited material, the two specimens are placed in P. ananas on 
morphological grounds. They may, however, need re-evaluation if a larger sample 
ever becomes available from East Ogwell. 

GEOL. I5, 5. 24 


230 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


Phillipsastrea rozkowskae sp. nov. 
Plate 6, figs. I-4 


DERIVATION OF NAME. The species is named after Professor Maria Rdzkowska 
(Poznan, Poland). 


Dracnosis. Pseudocerioid Phillipsastrea. Tabularium diameter 2:3-2-9 mm. 
with 12 to 15 major septa (topotype sample). Septa of two orders, major with 
short, club-shaped dilatation against tabularium boundary, becoming extremely 
attenuate in tabularium; minor septa hardly thickened. Dissepiments in several 
rows with single vertically discontinuous series of horseshoe dissepiments. Tabular- 
ium structure simple, with incomplete tabulae. 


HototyrPe. BM(NH) R46156. Lower Frasnian; road cutting, south side, 
25 yd. west of Ramsleigh Quarry entrance, East Ogwell, near Newton Abbot. 


MatTErRIAL. BM(NH) R46156-57. Horizon and locality as for holotype. 
DISTRIBUTION. Type locality only. 


DESCRIPTION. Massive, pseudocerioid colonies with predominantly pentagonal 
corallites separated by straight to slightly zigzagged pseudothecae. Only two frag- 
ments are available and details of colony shape, size and external features are 
unknown. 

The septa, major and minor, are 0:05-0:15 mm. thick peripherally. They are 
generally straight but may occasionally be very slightly flexed in the dissepimen- 
tarium. The major septa are dilated up to 0:35 mm. across for a length of 0°6 to I 
mm. just outside the tabularium. The minor septa are only slightly thickened in 
the same area. The latter do not penetrate the tabularium but the major septa, 
extremely attenuated, extend usually to within 0-4 mm. of the axis where they are 
usually curved into a very faint vortex. There is no dilatation of the axial ends of the 
major septa. Carinae are not developed and the septa are usually smooth through- 
out. 

Dissepiments are usually uniserial between adjacent septa. The trace of the 
horseshoe dissepiments, corresponding in position with the septal dilatation, forms a 
well marked wall around the tabularium. 

In longitudinal-section, the dissepimentarium is composed of several series of 
variably shaped dissepiments, from near flat to quite globose. Just outside the 
tabularium, the dissepimental surface rises to a crest formed by a somewhat dis- 
continuous vertical series of horseshoe dissepiments. Steep sloping vesicles are 
occasionally developed between the horseshoe dissepiments and the tabularium. 

The structure of the tabularium is simple. Tabulae are incomplete, distally 
concave plates or low elongate vesicles. They are arranged to give a flat or slightly 
concave surface to the tabularium. 

The few data available for the species are summarized in Table 6. 


Discussion. P. rozkowskae is probably the species of Phillipsastrea which most 
closely approaches Frechastraea. Its septa are very similar to the typical 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 231 


frechastraeid form (see p. 232) and the series of horseshoe dissepiments is relatively 
poorly developed for Phillipsastrea. 

P. rozkowskae is similar in its pseudocerioid growth form to P. smithi (Rézkowska), 
P. ananas (Goldfuss) and P. macrommata (F. A. Roemer). It differs from the latter 
two, however, through its smaller tabularium size and lower At/A ratio as well as 
the character of its septal thickening. P. smitii is distinguished by very strong 
septal dilatation forming a wide, dense wall around the tabularium. On the axial 
side of this wall, the major septa are represented by thick lobes only, and do not 
cross the tabularium towards the axis. 


Genus FRECHASTRAEA nov. 


DERIVATION OF NAME. The genus is named after Fritz Frech (1861-1917). 


Diacnosis. Massive rugose corals, pseudocerioid, astraeoid or thamnasterioid. 
Corallites small with clearly defined wall at tabularium junction. Septa of two 
orders, major and minor, generally slightly thickened against tabularium junction 
and strongly attenuate in tabularium. In longitudinal-section, dissepiments small, 
globose. Septal trabeculae arranged in a fan usually on the series of dissepiments 
adjacent to tabularium. Horseshoe dissepiments may rarely occur in this series. 
Dissepimental surface almost flat with a slight elevation surrounding tabularium. 
Tabulae complete or incomplete. 


TYPE SPECIES. Cyathophyllum pentagonum Goldfuss (1826 : 60, pl. rg, fig. 3). 
Frasnian; Namur, Belgium. 


DISTRIBUTION. Widespread in the Frasnian of Europe. 

Other species assigned to Frechastraea. Acervularia goldfusst de Verneuil & 
Haime (1850 : 161); ?Smithia boloniensis Edwards & Haime (1851 : 423); Smithia 
bowerbankt Edwards & Haime (1851 : 423); Smuithia micrommata C. F. Roemer 
(r852 : 197, pl. 51, figs. 20a, b); ?Acervularia roemert var. B concinna F. A. Roemer 
(1855 : 32, pl. 6, figs. rqga—c); Phillipsastraea sanctacrucensis Rozkowska (1953 : 59, 
text-figs. 32-33, pl. 2, figs. 8-10); Phillipsastrvaea pentagona (Goldfuss) var. minima 
Rodzkowska (1953 : 66, text-figs. 36-38, pl. 8, fig. 9). 

Discussion. Frechastraea embraces a well defined group of Devonian colonial 
rugose corals. Species here included in the genus have been previously assigned to 
Hexagonaria, Billingsastraea, Phillipsastrea or synonyms of these three genera. 

Workers in the last century, particularly Edwards & Haime, frequently placed 
pseudocerioid and astraeoid Devonian corals, including species of Frechastraea, in 
the Silurian genus Acervularia Schweigger. This similarity between the Silurian 
and Devonian forms is, however, quite superficial and Acervularia has long been 
considered unrelated to the phillipsastreids. More or less concurrent with the use 
of Acervularia, some astraeoid and thamnasterioid species of Frechastvaea were 
assigned to Smuthia, which is an objective synonym of Phillipsastrea. 

Lang & Smith (1935 : 559) referred to Prismatophyllum pentagona (Goldfuss) in 
their remarks on the genus Prismatophyllum. Prismatophyllum Simpson is con- 


232 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


sidered a junior synonym of Hexagonaria Giirich (see Lang, Smith & Thomas Ig4o : 
104). The type species of both, P. prisma Lang & Smith and H. hexagona (Goldfuss) 
respectively, are characterized by typical disphyllid dissepimentaria with the septal 
trabeculae sloping axially and upwards throughout. JF vechastraea differs from these 
chiefly by the possession of a full trabecular fan based on the series of dissepiments 
adjacent to the tabularium. In addition, Hexagonaria shows no tendency to the 
development of horseshoe dissepiments and lacks the strongly defined tabularium 
junction characteristic of the present genus. 

Many of the forms assigned to Hexagonaria by Moenke (1954) also do not possess 
a disphyllid dissepimentarium. These species, however, are morphologically quite 
distinct from those referred to Frechastraea and have been placed in Marisastrum 
by Rézkowska (1965 : 262) and Scrutton (1967 : 270). 

Schouppé (1958 : 235) included species of F’vechastraea in the genus Billingsastraea 
Grabau. The type species of Billingsastraea is B. vernewls (Edwards & Haime). 
The holotype is missing but Ehlers & Stumm (1953 : 2) have described corals under 
that name which appear in all respects to satisfy the original diagnosis. Bullingsas- 
traea sensu stricto is thus characterized by a broadly reflexed dissepimentarium in 
which there is no tendency to produce horseshoe dissepiments. The septa are 
uniformly thin from the periphery to the axis of the corallite, usually with no sign 
of dilatation, and the strongly marked tabularium junction of Frechastraea is lacking. 
Oliver (1964 : 2-3) criticized Schouppé’s interpretation of Bullingsastraea and 
suggested that there is probably no close relationship between that genus and the 
phillipsastraeids. The writer subscribes to this view (Scrutton 1967 : 276) and 
species of Frechastraca are here considered quite distinct from Bullingsastraea. 

Schouppé (1958 : 156) recorded a well developed series of horseshoe dissepiments in 
P. hennai, the type species of Phillipsastrea. Until that time, species of Frechastraea 
had been widely assigned to that genus. They are certainly most closely related to 
Phillipsastrea but may be distinguished from it by the rarity with which horseshoe 
dissepiments occur. J’rechastraea is also strongly characterized by its septa (compare 
Text-figs. 4b & 4c)—uniformly thick in the dissepimentarium with a short club- 
shaped thickening against the tabularium boundary, and major septa strongly 
attenuate in the tabularium. In Phillipsasirea the septa are more spindle-shaped, 
and may be equally thin in the tabularium and peripheral parts of the dissepimen- 
tarium; frechastraeid type septa are only rarely known. Finally species of Frechas- 
traea tend to have smaller individuals—seldom greater than 2mm. tabularium 
diameter—than species of P/ullipsastrea. 

The occasional horseshoe dissepiments developed in the dissepimentaria of species 
of Frechastraea are recorded here for the first time. It is thought that the genus 
descended from a phillipsastreid ancestor chiefly through the progressive elimination 
of horseshoes from the dissepimentarium. P. vozkowskae, in particular, shows a 
tendency toward frechastraeid characters and is considered a possible intermediary 
between the two genera. It may be significant in an evolutionary sense that 
R6zkowska (1953) did not record horseshoes in species of F’rechastraea from mainly 
Upper Frasnian horizons in Poland whilst they can often be seen in the dissepi- 
mentaria of the same species among the English Lower Frasnian material. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 233 


Frechastraea pentagona pentagona (Goldfuss) 


Plate 6, fig. 5; Plate 7, figs. 1-5 


1826 Cyathophyllum pentagonum Goldfuss : 60, pl. 19, fig. 3. 

1840 Astrea (Favastrea) pentagona (Goldfuss) Lonsdale : 697 pars, pl. 58, fig. 1 (non 1a). 

1841 Astvea pentagona (Goldfuss); Phillips : 11, pl. 6, fig. 15. 

1851 Acervularia pentagona (Goldfuss) Edwards & Haime : 418. 

1853 <Acervularia pentagona (Goldfuss); Edwards & Haime : 238, pl. 53, figs. 5-50. 

1883 Acervularia pentagona (Goldfuss); C. F. Roemer : 352, text-fig. 70. 

1885 Phillipsastrea pentagona (Goldfuss) Frech : 54 pars, pl. 3, figs. 7, 74, ?8, 10; pl. 8, fig. 3. 
1935 Prismatophyllum pentagona (Goldfuss) Lang & Smith : 559. 

1953 Phillipsastvaea pentagona (Goldfuss); Rdézkowska : 64, text-figs. 36-39, pl. 8, fig. 7. 


But not: 
1952 Phillipsastvaea pentagona (Goldfuss); Soshkina : 102, pl. 43, fig. 145. 


Diacnosis. Pseudocerioid Frechastraea with mean tabularium diameter I-09 mm. 
and 7 to 13 major septa (East Ogwell sample). Smooth, non-carinate septa. 
Horseshoe dissepiments very rarely developed. Tabulae complete or incomplete. 
Increase axial or lateral. 


LECTOTYPE (selected by J. W. Pickett im press). Original of Goldfuss 1826, pl. 
19, fig. 3 which is specimen 206 in the Goldfuss Collection of the Geologisch-Palaon- 
tologisches Institut, Bonn. Goldfuss (1826 : 60) gave the horizon and locality as 
the “‘ Transition limestone of the Namur region’, Belgium. Frasnian. 


MATERIAL. Ramsleigh Quarry: OUM D279 (Colony 1), BM(NH) R23400 
(Colony 3), BM(NH) R5635 (Colony 4). Other measured specimens: BM(NH) 
R676, TM(JB) 305A. 

Road cutting, 20 yd. west of Ramsleigh Quarry entrance: OUM D538 (Colony 2). 
Other measured specimen: OUM D537. 

Road cutting, 40 yd. west of Ramsleigh Quarry entrance. Measured specimen: 
OUM D532. 


DISTRIBUTION. England: Lower Frasnian limestones, Ramsleigh Quarry and 
adjacent road cutting, East Ogwell, near Newton Abbot, south Devon. Also 
Frasnian of Belgium, Germany and Poland. 


DESCRIPTION. Colony shape, external features and overall dimensions are unknown 
as all the English material is fragmentary. R6dzkowska (1953 : 64), however, 
described Polish representatives of this subspecies as thick, tabular colonies up to 
6cm. in diameter and 6cm. in height. Goldfuss’ original specimen is a thick, 
rectangular block with the convex upper surface measuring 7cm. by 8cm. The 
corallites have slightly depressed tabularia with a low, encircling ridge formed by the 
innermost series of dissepiments. Rdzkowska gave no details of a holotheca and 
it is not preserved in any of the English specimens. 

The colonies are massive, pseudocerioid, tending rarely to astraeoid or thamnas- 
terioid. Individual corallites, usually pentagonal or hexagonal in shape, are separated 
from each other by a straight or zigzagged pseudotheca. Occasionally the pseudo- 
theca may break down when the septa are more or less confluent from one corallite 
to the next, 


COLONIAL PHILLIPSASETRAETL DAE HROM SE. DEVON 


234 


Colony | 


40 
30 


-—<——--"- 


10 


40 


30 


10 


14 


1:2 


16 


1:4 


i722 


Total sample 


(mm) 


dt 


(mm) 


dt 


4 


Colony 


3 


Colony 


2 


Colony 


1 


Colony 


Total sample 


Frechastraea pentagona pentagona. 


FIG. 13. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 235 


TABLE 7.—Statistical data for some characters of Frechastraea pentagona pentagona. 


Total sample Colony 1 Colony 2 Colony 3 Colony 4 
N 424 (8) 60 60 60 60 
O.R. 0:8-1°5 O:Q-I°I 0:9-I°3 I*O-I-2 I-O-1°3 
x I-09 I-00 1°04 1:09 I-20 
dt Ss 0:10 0:059 0-084 0:067 0-068 
C.V. 9°38 5°97 8-13 6:12 5°65 
S.E.m 0-005 0-0077 O:OII 0: 0086 0-0087 
O.R. 7-12 7-11 8-11 g-12 Q-12 
xX 10-12 9:80 9°73 10°12 9:90 
n s 0-32 0-38 0-30 0°15 0-24 
C.V. 3°15 3°85 3°04 1°48 2°43 
S.E.n 0-o16 0-049 0-038 0:019 0-031 


O.R. 6:67-12:00 7:78-II-:II 7:69-10:00 §8:-33-10:00 7:50-10-00 


x 9°36 9-86 9°73 9°32 8-30 
n/dt s 0-59 0:25 0-30 0:44 0:33 

G.V. 6°34 2°54 3°04 4°69 3°93 

S.E.n 0-029 0-032 0-038 0-056 0-042 
Graphs :— 

r 0:92 0-94 0:74 0:99 0:91 
n/dt a 3°13 6°35 3°51 2°25 357 

b 6°72 3°49 6-09 7°67 5°63 

it —1-00 —o-:90 —o-96 —0:99 —0-94 
i a —5:°81 —4:21 —6-10 —6:56 —4:83 

b 15°68 14°05 15°75 16°42 14:07 

A At At/A Graph:—At/A 

O.R. 0:O0gI—0:16 0:0078—0: OI! 0:057-0-099 
xX 0-12 0:0093 0:079 r 0:38 
Ss 0-024 0:0013 0:015 a 0:055 
C.V. 20°25 14°38 18-63 b 0:0027 
S.E.n 0:0086 0+00047 0:0052 


The septa, both major and minor, are straight and uniformly thick, about 0-05 mm. 
across, in the dissepimentarium. At the tabularium junction the major septa, and 
to a lesser degree the minor, are dilated to form a short bulbous thickening. This 
thickening, associated with the clearly defined junction between tabulae and dissepi- 
ments, gives rise to a strong internal wall at this point. The minor septa are normally 
confined to the dissepimentarium and only occasionally show as slight projections 
into the tabularium. The major septa, however, continue into the tabularium as 
extremely thin processes, usually extending halfway or slightly more towards the 
axis and sometimes reaching the axis itself. There is a strong tendency for the axial 
ends of the longer major septa to fuse. The thin septal elements in the tabularium 


236 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


are easily obliterated by slight recrystallization, but even in the best of the material 
examined there was no sign of thickening of the axial ends of the major septa. 

The dissepiments are almost always uniserial between adjacent septa and appear 
moderately spaced in cross-section. In longitudinal-section, the dissepimentarium 
is composed of several series of small, evenly developed, well arched dissepiments. 
Their vertical height varies between o-r and 0-2mm. The dissepimental surface is 
usually flat but may occasionally slope slightly away from the tabularium boundary. 
At the latter position, a dissepiment may very rarely be modified into a horseshoe 
shape but there is no tendency to develop a series of horseshoe dissepiments. No 
more than two, or possibly three horseshoes have been observed in continuous vertical 
succession. 

The tabularium structure is often partially obscured by slight recrystallization. 
The tabulae are usually flat lying and may be complete or interleaved. Occasionally, 
however, they slope downwards away from from the axis with an overall tent or bell 
shaped appearance. In some cases there is evidence of axial structures suggesting 
the vesicles described in the tabularium of Frechastraea goldfussi (see p. 249). 
Unfortunately, poor preservation and sometimes septal traces obscure the axial area 
at these points and the relationships of the tabulae are not clear. In the more 
simply constructed tabularia, the tabulae have an average vertical spacing of about 
0-2 mm. 

Both axial and lateral increase have been observed in this subspecies, the latter 
being more common. 

A sample of eight colonies from the limestones exposed in Ramsleigh Quarry and 
the adjacent road cutting has been statistically analysed. our of the colonies have 
also been analysed individually. The statistics are listed in Table 7 and illustrated 
graphically in Text-figs. 13 and r6. 

Discussion. Both Lonsdale (1840 : 697) and Frech (1885 : 54) included Acer- 
vularia goldfusst or specimens belonging to this species in their interpretation of 
Cyathophyllum pentagonum. The two species are superficially extremely similar, 
although on close inspection they can be readily distinguished. The details of the 
differences are given below (p. 253) under F. goldfussi. 

The most recent thorough investigation of Frechastraea pentagona pentagona is by 
Rézkowska (1953 : 64) as a species of Phillipsastrea. Her material has a slightly 
larger mean tabularium diameter than the English sample but there is no doubt that 
they belong to the same subspecies. 


Frechastraea pentagona (Goldfuss) minima (Rozkowska) 
Plate 8, figs. 1-3 
1953 Phillipsastraea pentagona (Goldfuss) var. minima Roézkowska : 66, text-figs. 36-38, pl. 8, 
fig. 9. 
1953 Phillipsastraea bowerbanki (Edwards & Haime); Rdzkowska : 67, pl. 8, figs. 3, 4. 
1959 Phillipsastvaea pentagona (Goldfuss) var. micrommata (C. F. Roemer); Middleton : 156, 
text-fig. 6f. 
Dracnosis. Pseudocerioid to astraeoid to thamnasterioid Frechastraea. Mean 
tabularium diameter 0:96mm, with 7 to 12 major septa (East Ogwell sample). 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 237 


Tabularia somewhat unevenly spaced. Septa sinuous and only slightly dilated at 
tabularium junction. Horseshoe dissepiments rare. Increase axial or lateral. 


Ho.otyrPe. Ag8 in the Collections of the Polska Akademia Nauk, Pracownia 
Palaeozoologii, Poznan, Poland. Upper Frasnian, Psie Goérki, Kielce, Poland. 


MATERIAL. Ramsleigh Quarry: GSM 73119 (Colony r), GSM 11822 (Colony 2), 
GSM 73118 (Colony 3). Other measured specimens: BM(NH) R46371, BM(NH) 
R23266. Additional material: GSM 11821, GSM 11823. 


DISTRIBUTION. England: Lower Frasnian of Ramsleigh Quarry, East Ogwell, 
near Newton Abbot, south Devon. Also Upper Frasnian of Kielce, Poland. 


DEscriPTION. Details of size, shape and external features of the English material 
are unknown as it is fragmentary. Rozkowska (1953 : 67), however, described the 
holotype as a low, plate-like colony measuring 3°5 cm. by 1-6 cm. in surface area. 

Individual corallites are seldom completely surrounded by an external pseudotheca 
and usually the septa are confluent or subconfluent between them. All gradations 
from the pseudocerioid to the thamnasterioid stage are usually present in the same 
colony and this is accompanied by a general increase in the distances separating the 
tabularia. Where an external pseudotheca is present, it is formed by the deflection 
of the peripheral septal ends. 

The septa, 0°05 mm. or less in thickness, are uniformly thin and are gently sinuous 
between tabularia. They are usually smooth sided. Rarely there appears to be a 
slight separation of the trabeculae, which remain unthickened, resulting in dis- 
continuous septa. At the tabularium junction, the septa are slightly dilated for 
about o-I mm. of theirlength. Within the tabularium, the major septa thin abruptly 
and continue as very fine filaments more or less to the axis, where the ends of two 
or more adjacent septa may fuse. The minor septa do not penetrate into the 
tabularium. 

The dissepiments are almost always uniserial between adjacent septa. The 
tabularium junction is sharply defined in cross-section, giving the appearance of an 
internal wall. 

In longitudinal-section, the dissepimentarium is composed of several series of 
small, well arched dissepiments. They may vary somewhat in size and their height, 
usually about o-I mm., ranges from 0-05 to 0:25mm. The surface of the dissepi- 
mentarium is flat peripherally, usually rising slightly with the more globose dissepi- 
ments adjacent to the tabularium. Horseshoe dissepiments may rarely develop in 
the latter position. 

The tabularium structure is simple and the tabulae may be complete or incomplete. 
The complete tabulae are either flat or sag slightly in the middle. The incomplete 
tabulae are flat to slightly bowed and interleaved with each other, or in the form of 
long weakly arched vesicles. The vertical spacing of the tabulae may vary between 
o-r and 0-3 mm., but is normally about 0-15 mm. in the more regularly developed 
tabularia. 

Examples of both axial and lateral increase have been observed. 

A statistical analysis has been made of a total sample of 5 colonies from Ramsleigh 


238 COLONIAL PHILLIPSASTRAEIDAE FROM 5.E. DEVON 


100 


90 


80 


70 


60 


40 


30 


20 


06 0-7 0-8 0-9 1:0 11 1:2 13 14 
dt (mm) 


0-6 0:8 1:0 1:2 14 0:6 0-8 10 1:2 14 
dt (mm) dt (mm) 


Total sample Colony | Colony 2 Colony 3 


Fic. 14. Frechastraea pentagona minima. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 239 


TABLE 8.—Statistical data for some characters of Frechastvaea pentagona minima. 


Total sample Colony 1 Colony 2 Colony 3 
N 240 (5) 60 60 60 
O.R. 0°7-1'°3 O-7-I°I o-8-1°I O-Q-I'I 
xX 0:96 0:90 0°93 0:98 
dt Ss Oasn 0-079 0-082 0°055 
C.V. 10-98 8-78 8-85 5°57 
S.E.n 00068 0:O10 O:OII 00-0071 
O.R. 7-12 8-10 7-11 8-10 
X 9°54 9°61 9°25 9°52 
n Ss 0-42 0°23 0°54 0:36 
c.V. 4°42 2°42 5:86 3°77 
S.E.n 0:027 0-030 0:070 0:046 
O.R. 7°69-12°87 8-18-12:87 7:78-11:26 8:8Q-II-1I2 
Xs 10:05 10°72 IO-O1 9°72 
n/dt s 0:64 0°73 0°35 0:20 
C.V. 6:40 6:82 3°54 2°04 
S.E.n 0°42 0-094 0-046 0:026 
Graphs :— 
r 0-98 0°77 0°95 0°97 
n/dt a 4:00 2°94 6:61 6:58 
b 57 6:96 3°12 3°07 
n/dt r —o:98 —0o-99 —o:88 —0-92 
a —6:'II — 9°24 —4°32 —3°63 
dt 
b 15°91 19:06 14:01 13°27 
A At At/A Graph :—At/A 
O.R. O:II-O-1I5 0:0065-0:010 0:054—0-071 
aK: O-12 0:0075 0-062 r 0:84 
s 0-017 0:0016 0:0076 a 0-092 
C.V. 14°52 21°37 12°21 b —0:-0036 
S.E.n 0:0078 0:00072 0:0034 


Quarry. Three of these colonies have also been analysed individually. Thestatistics 
are listed in Table 8 and illustrated graphically in Text-figs. 14 and 16. 


Discussion. R6dzkowska (1953 : 66) erected this subspecies as a variety of 
“ Phillipsastraea pentagona’”’ on only one specimen. Although the tabularia of her 
specimen (0-6-0-8 mm. diameter) are slightly smaller than those in the English 
examples, the colonies are in complete morphological agreement and are undoubtedly 
the same subspecies. The holotype clearly shows the characteristic pseudocerioid 
grading to thamnasterioid nature of the corallites and the irregular spacing of the 
tabularia described above. 


240 COLONTAL PHILELPSAS TRAE TDAE EAOM ss Dis ViON; 


The specimen described by R6zkowska (1953 : 67) as “‘ Phillipsastraea bowerbankt ” 
is indistinguishable from GSM 73118 (Pl. 8, fig. 1) of the present material and is 
thus also referable to this subspecies. The slight morphological differences between 
these specimens and the holotype of F’. pentagona minima lie within the range of 
variation to be expected. fF. pentagona minima is quite distinct from FP. bowerbanki 
which is almost exclusively thamnasterioid and has considerably larger tabularia, 
wide and regularly spaced (see p. 253). 

Two fragments from Ramsleigh Quarry (GVM 26/7 and 26/8), misidentified as 
Phillipsastraea pentagona var. micrommata by Middleton (1959 : 156), also belong to 
this subspecies. 

F. pentagona pentagona and F. pentagona minima are very similar in quantitative 
terms. Only 0-13 mm. separates their mean tabularium diameters. In addition, 
their lines on the graphs plotting septal number against tabularium diameter and 
tabularium area against corallite area are very similar in both slope and position 
(Text-fig. 16). Nevertheless, because of the large sample sizes, tests of statistical 
discrimination show the subspecies to differ significantly in both dt (Table ro) and 
their lines on the former of the two graphs. 

F.. pentagona minima is distinguished principally on qualitative characteristics, and 
without prior separation on these grounds, could not be differentiated from F. 
pentagona pentagona on quantitative data alone. F. pentagona pentagona is pseudo- 
cerioid, tending slightly to astraeoid, with straight septa. The septa in F. pentagona 
munima, on the other hand, are generally sinuous and associated with a wide range in 
form from pseudocerioid to thamnasterioid. The tabularia also tend to be irregularly 
spaced. In the material so far examined, no difficulty has been found in distinguish- 
ing quite clearly between the two subspecies. 

Both occur in association in the Lower Frasnian Ramsleigh limestones in England 
and the Upper Frasnian of Kielce in Poland (R6zkowska 1953). In the English 
fauna, F. pentagona pentagona and F. pentagona minima occur in approximately 
equal numbers whilst R6zkowska’s figures suggest a ratio of rr : r in favour of F. 
pentagona pentagona in the Kielce area. 


Frechastraea micrommata (C. F. Roemer) 
Plate 8, figs. 4, 5 
1852 Smithia micromata C. F. Roemer : 197, pl. 51, figs. 20a, b. 


But not: 

1885 Phillipsastvea pentagona (Goldfuss) var. micrommata (C. F. Roemer) Frech : 56, pl. 3, figs 
11-13; pl. 8, fig. 1. 

1953 Phillipsastraea pentagona (Goldfuss) var. micrommata (C. F. Roemer); Rozkowska : 66, 
text-figs. 36-38; pl. 8, fig. 8. 

1958 Phillipsastvaea pentagona (Goldfuss) var. micrommata (C. F. Roemer); Bulvanker : 123, 
pl. 60, figs. 1-3; pl. 61, figs. 4, 5. 

1959 Phillipsastraea pentagona (Goldfuss) var. micrommata (C. F. Roemer); Middleton : 156, 
text-fig. 6f. 


DiaGnosis. Pseudocerioid tending to astraeoid Frechastraea. Mean tabularium 
diameter 1:42 mm, with 18 to 21 septa (holotype). Major and minor septa not 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 241 


distinguished as septa penetrating the tabularium exceedingly rare; septa non- 
carinate. Tabularium structure very simple, usually composed of complete tabulae. 
Increase lateral. 


LECTOTYPE (here chosen). Specimen no. 34 in the collections of the Geologisch- 
Palaontologisches Institut, Bonn. Original of Roemer’s (1852, pl. 51) figures 20a, 0. 
Frasnian; Ferques near Boulogne, France. 


DEscrIPTION. Colony irregularly disc shaped, 8 cm. in diameter and 4 cm. high; 
covered basally by a strongly concentrically ridged holotheca. The corallites are 
pseudocerioid tending to astraeoid with a thin, usually zigzagged, pseudotheca. 

The septa are not normally distinguished as major and minor as with very rare 
exceptions they all end at the tabularium junction. The septa are about 0:05 mm. 
thick in the dissepimentarium and follow a straight or slightly sinuous course to the 
tabularium boundary where they may thicken slightly. Septa may occasionally 
form slight inward projections on the tabularium boundary and one septum was 
seen to penetrate the tabularium for a distance of 0-4 mm. 

The tabularium-dissepimentarium junction is a thin strong circular wall in cross- 
section. This wall appears to be the product of septal dilatation and thickening 
of the inner arms of the series of dissepiments adjacent to the tabularium. Some- 
times, however, the septa themselves appear to bend sharply at the boundary to 
form a segment of the wall. 

In longitudinal-section, the dissepimentarium is composed of several series of quite 
globose dissepiments normally 0-5—0-6 mm. in height. In narrow levels which can 
be traced from corallite to corallite, however, they become smaller, flatter and more 
closely spaced. The dissepimental surface is flat over most of its area but rises 
slightly to a crest adjacent to the tabularium. MHorseshoe dissepiments have not 
been observed. 

Tabularium structure is very simple, consisting in the main of complete flat or 
slightly bowed tabulae with occasional incomplete arched plates. The latter may 
be subsidiary to the complete tabulae or may interleaf to form the tabularium 
structure proper. 

One example of lateral increase has been observed. 

Measurements on twelve corallites showed tabularium diameter to range from 
I-3-I°5 mm., mean value 1-42 mm., with 18 to 21 septa. Mean n/dt, taking n to be 
half the number of septa in each corallite, is 6-94. 


Discussion. The above description is based on Roemer’s figured specimen only. 
Although no horseshoe dissepiments have been observed, the character of the species 
as a whole places it without doubt in Frechastraea. Full knowledge of the variation 
in dissepimental shape must await the description of further material belonging to 
this species. 

This is the first time that the type specimen has been sectioned and the slides show 
that Frech (1885 : 56) and subsequent authors have misidentified the species. The 
specimens placed by Frech and others in Smithia micrommata (as Phillipsastrea 
pentagona var. micrommata) are here assigned to F’. carinata sp. nov. which is described 
below. 


242 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


F. micrommata differs from all other known species of Frechastraea by the lack 
of any distinction between major and minor septa. In particular, it can be dis- 
tinguished from F. carinata by the latter’s septal carination and more complex 
tabularium structure. Data so far available show that tabularia in F. micrommata 
are somewhat larger than in F. cavinata (dt — I-02 mm.). 


Frechastrea carinata sp. nov. 
Plate 9, figs. I-3 
1885 Phillipsastrvea pentagona (Goldfuss) var. micrommata (C. F. Roemer) Frech : 56, pl. 3, 
figs. II-12, ?13; pl. 8, Pfig. 1. 
1953 Phillipsastraea pentagona (Goldfuss) var. micrommata (C. F. Roemer); R6ézkowska : 66, 
text-figs. 36-38, pl. 8, fig. 8. 
But not: 
1852 Smithia micrommata C. F. Roemer : 197, pl. 51, figs. 20a, b. 
1958 Phillipsastvaea pentagona (Goldfuss) var. micrommata (C. F. Roemer); Bulvanker : 123, 
pl. 60, figs. 1-3; pl. 61, figs. 4-5. 
1959 Phillipsastrvaea pentagona (Goldfuss) var. micrommata (C. F. Roemer); Middleton : 156, 
text-fig. 6f. 
DERIVATION OF NAME. The name refers to the presence of septal carinae, an 
important distinguishing feature of this species. 


Diacnosis. Pseudocerioid, tending to astraeoid and thamnasterioid Frechastraea. 
Mean tabularium diameter 1-02 mm. and between 8 and 14 major septa (topotype 
sample). Septa variably but typically carinate. Horseshoe dissepiments very 
rare. Tabulae mainly incomplete. Increase axial or lateral. 

HototyrpeE. OUM D309. Lower Frasnian; road cutting, 80 yd. west of Rams- 
leigh Quarry entrance, East Ogwell, near Newton Abbot, south Devon. 


MATERIAL. Ramsleigh Quarry: BM(NH) R23210 (Colony 1), BM(NH) R232rr 
(Colony 2), BM(NH) R23216 (Colony 3), BM(NH) R5640 (Colony 4). Other measured 
specimens: BM(NH) R677, BM(NH) R5634. 

Road cutting, 80 yd. west of Ramsleigh Quarry entrance. Measured material: 
OUM D309-310, OUM D535-6. 


DISTRIBUTION. England: Lower Frasnian limestones, Ramsleigh Quarry and 
the adjacent road cutting, East Ogwell, near Newton Abbot, south Devon. Also 
Frasnian of Germany (Harz) and Poland (Kielce). 


DEscrIPTION. Nothing is known of colony shape, size and external features from 
the present material. 

The colonies are pseudocerioid, tending to astraeoid and occasionally thamnasterioid 
in parts. Corallites are irregularly polygonal, usually pentagonal or hexagonal, and 
for the most part separated from each other by a straight or slightly zigzagged wall 
formed by the deflection of the peripheral septal ends. When this pseudotheca 
breaks down, the geniculate ends of the septa are more or less confluent with those 
of the adjacent corallite. 

The septa, of two orders major and minor, are variable in thickness but average 
about 0-05 mm. in the dissepimentarium where they may be sinuous. Occasionally 


COLONTAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 243 


corallites have a bilateral appearance when the septa tend to le parallel on either 
side of the tabularium. Within the tabularium, the major septa thin considerably 
to about 0:02 mm. in thickness and continue, as straight or flexuous filaments, more 
or less to the axis. Minor septa are confined to the dissepimentarium. Sometimes 
the axial ends of adjacent major septa fuse, or the axial ends of opposite septa are 
continuous across the tabularium. Signs of thickening of the axial ends of septa 
are very rare. 

The septa are variably carinate in the dissepimentarium. In exceptional cases 
the carinae may reach 0-4 mm. in width, but mostly they are between o-r and o-15 
mm. Their spacing varies but normally there are Io carinae per mm. of septal 
length. On individual septa, carination is heaviest in a zone of irregular width 
surrounding the tabularium, corresponding to the septal dilatation observed in 
Frechastraea pentagona and F’. goldfusst; occasionally, adjacent carinae may fuse 
along the septa in this zone. As they enter the tabularium, the septa rapidly become 
smooth. 

The dissepiments, moderately to closely spaced in cross-section, are almost 
exclusively uniserial between adjacent septa. The tabularium junction is sharply 
defined. 

In longitudinal-section the dissepimentarium consists of several series of regularly 
developed, small, arched dissepiments. Their height is usually between o-r and 
o-2mm. The dissepiments become progressively more globose towards the tabular- 
ium and against the tabularium boundary, horseshoe dissepiments occur very rarely. 
The surface of the dissepimentarium slopes slightly downwards and outwards from 
the tabularium and is flat lying peripherally. 

The tabularium structure is usually simple. The tabulae are commonly incomplete 
and may be flat or moderately arched. Their vertical spacing averages about 
o-2mm. In one specimen, OUM D310b, there is evidence of highly domed axial 
plates, occupying about one fifth of the tabularium diameter, with peripheral flat, 
or slightly bowed tabulae. This axial structure is not clearly developed but it 
appears to be similar to that described in F. goldfussz. 

Very few instances of increase have been observed but both axial and lateral are 
represented. 

A total sample ot ten colonies from Ramsleigh Quarry and the adjacent road 
cutting has been statistically analysed. our of the colonies have also received 
individual treatment. The statistics are listed in Table 9 and illustrated graphically 
in Text-figs. 15, 16. 

Discussion. Material assigned to this new species was formerly known, due to 
Frech’s (1885 : 56) work, as ‘Piillipsastrea pentagona var. micrommata (C. F. 
Roemer)’. Recently, however, the writer has been able to section Roemer’s 
figured specimen of Smithia micrommata, which is described above. This shows 
conclusively that Frech and all subsequent workers have wrongly interpreted 
Roemer’s species. 

Frech also placed Acervularia roemeri var. P concinna F. A. Roemer in synonymy 
with his P. pentagona var. micrommata. The original material of the former variety 
appears to be missing and F. A. Roemer’s illustrations (1855, pl. 6, figs. Iga—c) are 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


244 


40 


30 


10 


30 


20 


10 


Total sample 


(mm) 


dt 


(mm) 


dt 


ee eee eS 6 et es 


4 


Colony 


3 


Colony 


2 


Colony 


1 


Colony 


Total sample 


Frechastraea carinata. 


Fia, 15. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 245 


rather poor. They show no sign of septal carinae, however, and the septa themselves 
are spindle-shaped and thin peripherally—the phillipsastreid rather than the 
frechastraeid pattern. The present material is thus considered distinct from A. 
roemert var. f concinna. 

F. carinata is extremely close quantitatively to F. pentagona, with its mean tabular- 
ium diameter falling between that of F. pentagona pentagona and F. pentagona 
minima (Text-fig. 16). Statistical discrimination however reflects the high sample 


TABLE 9.—Statistical data for some characters of Frechastvaea carinata. 


Total sample Colony 1 Colony 2 Colony 3 Colony 4 
N 423 (9) 60 60 60 60 
O.R. 0: 8-1-3 o:8-1-0 0: 8-1-2 0: 8-1-2 I*O-1°3 
x I-02 0:93 0:96 I-02 I-16 
dt s O-II 0-057 0-081 0-069 0-064 
c.V. 10°56 6-18 8-44 6-81 5°47 
S.E.n 0:0052 0 +0074 0-010 0:0090 0-0082 
O.R 8-14 8-10 8-11 8-11 g-II 
x 9°75 9°42 9°35 9°87 9°95 
n Ss 0*34 0:29 0:40 0-19 0:12 
C.V. 3°51 3:07 4°29 I-89 I-18 
S.E.n 0-017 0:037 0+052 0-024 0:015 


O.R. 7°27-12°73 8:89-11'26 8-00-I11°II 8-33-12°50 7:50-12°50 


x 9:66 10-20 9°79 9°74 8-57 
n/dt s 0:68 0°32 0-41 0:58 0:39 

c.V. 7:07 3°13 4°22 5°90 4°50 

S.E.n 0-033 0-041 0:053 0:074 0-050 
Graphs :— 

r 0°95 I-00 0:93 0:70 0:89 
n/dt a 3:18 5:07 4°96 2:69 1-84 

b 6°52 4°73 4°60 qo 38} 7°82 

r —1-00 —1-:00 —o-96 —o-96 —1I1-:00 
Nes dt a —6-36 —5°59 —5:11 —8-30 —6-:06 

b 16-12 15°37 14°69 18-18 15°62 

A At At/A Graph:—At/A 

O.R. 0-10-0'17 0+0067—0: O11 0-052-0-088 
x 0°13 0:0082 0-063 r 0:77 
Ss 0-024 0:0013 0-:OII a 0+054 
C.vV. 18-45 15°86 17°68 b 0: 0012 
S.E.m 00-0081 0-00044 0+0037 


GEOL. I5, 5. 25 


240 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 
500 


400 


300 


200 


100 


‘030 


025 


-020 
At 


(sq. cms) 


015 


“010 


“005 
0:10 0-14 018 0:22 0:26 0:30 0:34 0:38 


A (sq. cms) 


n 
0-6 10 1:4 18 2:2 0-6 10 1:4 18 2:2 
dt (mm) dt (mm) 
F. pentagona pentagona —__ (*) F. pentagona minima —--—-——- (+) 
F. carinata ——-—-——_— (°) F. goldfussis ———— (:) F. bowerbanki ——--—--—= (#) 


Fic. 16. Graphical comparison of some quantitative characters for the species and sub- 
species of Frechastraea. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


247 


TABLE 10.—Statistical discrimination between some characters for species and subspecies of 
Frechastvaea. Significant values in bold; s = slope, p = position. 


Values of ‘‘t’’:— 


dt 


pentagona pentagona 
pentagona minima 
cavinata 

goldfussi 

bowerbankti 


Values of ‘‘z’’:— 


n/dt 


At/A 


pentagona pentagona 
pentagona minima 
cavinata 

goldfussi 


bowerbanki 


pentagona pentagona 
pentagona minima 
carinata 

goldfussi 


bowerbanki 


nd Oy Ug UO wD 


Drow Hy HY DU 


uo) 


pentagona pentagona 
pentagona 


15- 
9- 
55- 


11 


Qn ROO H 


041 


“724 
-946 


+326 
‘116 
1379. 
+533 
-196 
-724 


15- 


6: 


11- 


11 


minima 


388 


589 


041 


-335 


+326 


o:116 


WOoOH 


544 
000 
719 
496 


9. 
6: 


OH PO 


cavinata 


838 
589 


"724 
-946 
-335 


+562 
-426 


33/19) 
+533 


"5.44 
*O000 


goldfusst 


55-924 


+149 


I+562 


13-855 


-196 
724 
719 
496 


WoWN 


3-719 


bowerbanki 


0°149 


13-855 


3-719 


sizes and F’. carinata can be shown to be significantly different from both subspecies 
in dt and the plot of n against dt, and from F. pentagona pentagona alone in the 


plot of At against A (Table ro). 


Qualitatively, F’. carinata is distinguished by its sinuous, variably carinate septa. 
There is also a characteristic tendency for the majority of the septa in one corallite 
to follow the same directional trend in the dissepimentarium. fF. sanctacrucensis 
(R6zkowska), recorded so far only from Poland, is closest in general appearance to 


F. carinata. 


The former is clearly astraeoid, however, with considerably larger 


tabularia (dt ca. 2 mm., n 12-14), and its septal carination gives a distinctive “ string- 
of-pearls ”’ effect. 


1850 Acervularia goldfussi de Verneuil & Haime : 


Frechastraea goldfussi (de Verneuil & Haime) 


Plate ro, figs. 1-5; Plate 11, figs. 1, 2 


1826 Cyathophyllum ananas Goldfuss : 60 pars, pl. 19, fig. 4a (non fig. 4b). 
1840 Astrea (Favastrea) pentagona (Goldfuss) Lonsdale : 
161. 


697 pars, pl. 58, fig. 1a (non fig. I). 


248 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


1851 Acervularia goldfussi de Verneuil & Haime; Edwards & Haime : 417. 

1851 Acervularia limitata Edwards & Haime : 419. 

1853 Acervularia goldfussi de Verneuil & Haime; Edwards & Haime : 236, pl. 53, figs. 3, 3a. 
1853 Acervularia limitata Edwards & Haime; Edwards & Haime : 238, pl. 54, ?figs. 1, 1a. 
1881 Acervularia pentagona (Goldfuss); Schliiter : 89, pl. 9, figs. 4, 5. 

1883 Acervularia goldfussi de Verneuil & Haime; C. F. Roemer : 352. 

1883 Acervularia limitata Edwards & Haime; C. F. Roemer : 353. 

1885 Phillipsastyea ananas (Goldfuss) Frech : 49 pars. 

1885 Phillipsastrea pentagona (Goldfuss) Frech : 54, pars, pl. 3, ?figs. 6, 9. 

1951 Phillipsastvaea limitata (Edwards & Haime); Soshkina : 97, pl. 17, fig. 2; pl. 18, fig. 2; 


pl. 23, fig. 4. 

1952 Phillipsastvaea limitata (Edwards & Haime); Soshkina : rot, pl. 42, fig. 142. 

1953 Phillipsastvaea goldfussi (Edwards & Haime); Rdzkowska : 62, text-figs. 35-37, pl. 8, 
figs. 5, 6. 

1958 Billingsastraea goldfussi (Edwards & Haime) Schouppé : 236, text-figs. 25, 26. 

1959 LPhillipsastraea goldfussi (Edwards & Haime); Middleton : 156, text-fig. 6d. 


But not: 
1881 Heliophyllum cf. limitatum (Edwards & Haime) Schliiter : 87, pl. 8, figs. 1, 2. 


Diacnosis. Pseudocerioid Frechastraea. Mean tabularium diameter 1:53 mm. 
and between 7 and 17 major septa (East Ogwell sample). Septa smooth, very rarely 
carinate, usually with lobate thickening on axial ends of major septa. Dissepi- 
mentarium occasionally with imperfect series of horseshoe dissepiments at tabularium 
boundary. Tabularium composed of complete or incomplete tabulae, rarely with 
axial domes of horseshoe section. Increase axial or lateral. 


HoLotyPe. (see de Verneuil & Haime, 1850: 161). The original of Goldfuss’ 
(1826, pl. 19, fig. 4a) illustration of Cyathophyllum ananas. Frasnian; Namur, 
Belgium. This specimen is either mislaid or lost. 


MATERIAL. Ramsleigh Quarry: TM(JB)31r0 (Colony 1), BM(NH) R46370 
(Colony 2), TM(JB)306 (Colony 3), BM(NH) R23208 (Colony 4), BM(NH) R46369 
(Colony 5), TM(JB)307 (Colony 6), BM(NH) R23217 (Colony 7), BM(NH) R46367 
(Colony 8), BM(NH) R46368 (Colony 9), BM(NH) R23302 (Colony ro). Other 
measured specimens: TM(JB)305B, TM(JB)311-313, TM(JB)318, BM(NH) R46374, 
BM(NH) R5636, BM(NH) R5642, BM(NH) R5648, BM(NH) R23301, OUM D530-1, 
OUM D539-41. 

South Devon: GSM (Geol. Soc. Coll.) 6183. 


DisTRIBUTION. England: Lower Frasnian limestones, Ramsleigh quarry, near 
Newton Abbot, south Devon. Also Frasnian of Belgium, Germany, Poland and 
U.S.S.R. (Timan); ? Frasnian of Spain. 


DESCRIPTION. The specimens are incomplete colonies frequently comprising 
more than 200 corallites. Colony shape, size and external features are unknown 
from the present material but according to Rézkowska (1953 : 62) Polish representa- 
tives of the species are hemispherical or lenticular colonies up to 7:5 cm. diameter 
and 3°5 cm. in height, covered basally by a holotheca. Where seen in the English 
material, the holotheca is about o-I mm. thick (Pl. 10, fig. 3). The calices, after 
R6zkowska, are deep with a flat floor, surrounded by an annular rim at the tabularium 
boundary. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 249 


The colonies are massive, pseudocerioid. The corallites, usually pentagonal or 
hexagonal, are separated from each other by a strong, straight or more frequently 
zigzagged pseudotheca. Infrequently the pseudotheca may break down in part 
when the septa are more or less confluent from one corallite to the next. 

In the dissepimentarium the septa, major and minor, are usually about 0-05 mm. 
but may occasionally reach 0-2 mm. in thickness. They are straight and are variably 
dilated for a short length against the tabularium boundary. The major septa 
continue as extremely thin processes across the tabularium to the axis where they 
develop a variable lobate thickening. | Usually these septa are fractionally with- 
drawn from the axis when their dilated ends form a pseudoaulos. The minor septa, 
normally less dilated than the major, are not continued beyond the thickened portion 
which may or may not project slightly into the tabularium. The septa are usually 
smooth sided but may occasionally be lightly carinate. 

The dissepiments appear fairly widely spaced in cross-section and are almost 
always uniserial between adjacent septa. Occasionally the traces of horseshoe 
dissepiments can be distinguished around the periphery of the tabularium, corre- 
sponding to the zone of septal dilatation. The tabularium junction itself is sharply 
defined. 

In longitudinal-section the dissepimentarium is composed of several series of 
small, well arched dissepiments. The number of series is variable, however, and 
may rarely be as low as two. Usually the dissepiments are regularly developed with 
a height of about 0-2 mm. and become somewhat more globose at the boundary with 
the tabularium. Occasionally, however, the series immediately adjacent to the 
tabularium may become modified in part to form an incomplete and irregular series of 
horseshoe dissepiments. The dissepimental surface slopes away from the tabularium 
for a short distance and is flat lying peripherally. 

The tabularium structure is usually simple, varying from complete flat to slightly 
domed tabulae, to wide slightly arched incomplete vesicular tabulae. The vertical 
spacing of the plates varies between 0-I mm. and 0-5 mm. but is usually about 0-2 
mm. Occasionally steep sided complete tabulae with narrow flat crests are developed 
and rarely highly globose vesicles with a horseshoe-shaped section appear in the axis 
of the tabularium. When two or three of the latter vesicles are superposed, peripheral 
plates slope steeply downwards and outwards from them. 

Increase is axial or lateral, the latter occurring more commonly. 

A statistical analysis has been made of specimens of this species from Ramsleigh 
Quarry. The total sample comprises 25 colonies, 10 of which have been analysed 
individually. The statistics are given in Table rr and the data is presented 
graphically in Text-figs. 16-18. 

Discussion. This species was erected by de Verneuil & Haime (1850 : 161) ina 
fossil list, but as they stated that their new species was Cyathophyllum ananas 
Goldfuss (1826, pl. 19, fig. 4a, non fig. 4b) their designation is valid. Acervularia 
goldfussi was later described in some detail by Edwards & Haime (1851, 1853) and 
many subsequent workers have mistakenly attributed the species to these authors. 

The lectotype of Acervularia limitata Edwards & Haime selected by Soshkina 
(1951 : 97) is lost and the figure of the specimen (Edwards & Haime 1853, pl. 54, 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


250 


(mm) 


dt 


(mm) 


dt 


Total sample 


Tabularium diameter frequency curves for ten colonies of Frechastvaea goldfusst. 


FIG. 17. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 251 


1:0 1-2 1-4 16 1:8 2:0 2:2 
dt (mm) 


T Total sample 


Fic. 18. Graphs of septal insertion and septal-tabularium ratio: tabularium diameter for 
ten colonies of Frechastvaea goldfusst. 


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COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 253 


figs. I, Ia) is of uncertain affinity. The only survivor of the original syntypes of 
Acervularia limitata appears to be the specimen figured by Lonsdale (1840 pl. 58, 
fig. Ia, non fig. 1) as Astrea (Favastrea) pentagona which is GSM (Geol. Soc. Coll.) 
6183. This specimen is conspecific with Frechastraea goldfusst. 

Frech (1885 : 49, footnote) considered Acervularia goldfussi as interpreted by 
Edwards & Haime (1851, 1853) to be transitional in form between his Phillipsastrea 
ananas and ‘P.’ pentagona and accordingly split the former species between the 
latter two. This explains the apparent inconsistencies in Frech’s synonymies. 
Under P. ananas (p. 49) he placed Cyathophyllum ananas Goldfuss (1826 pl. 19, 
figs. 4a, b) whilst under P. pentagona he listed ‘ Acervularia goldfussi de Verneuil & 
Haime 1850 p. 161 e.p.’. Frech considered Edwards & Haime’s (1853, pl. 53, 
figs. 3, 3a) figured specimen of A cervularia goldfussi as conspecific with his P. pentagona. 

Most subsequent authors appear to have interpreted F. goldfusst on Edwards & 
Haime’s figures and descriptions and to have considered it worthy of specific rank, 
although closely related to F. pentagona. In the absence of Goldfuss’ type specimen, 
this interpretation is followed here. The similarity between F. goldfussi and F. 
pentagona pentagona is considerable, both being pseudocerioid with essentially 
straight, non-carinate septa. Differences are confined to small details such as the 
lobate thickenings on the axial ends of the major septa in F. goldfussi and the higher 
incidence of horseshoe dissepiments in this species. F. goldfussi and F. pentagona 
pentagona are, however, clearly differentiated on quantitative characters (Text-fig. 16 
and Table 10). The former has a considerably larger tabularium diameter than the 
latter and the two are significantly different in their growth lines on graphs plotting 
n against dt and At against A. Both differ strongly from Phillipsastrea ananas 
(described on p. 228) through the larger dimensions, the spindle-shaped septa, 
complex tabularium and row of well developed horseshoe dissepiments of the latter. 

Rozkowska (1953 : 62 et seg.) has described ‘ Phillipsastraea’ goldfussi in detail 
from the Upper Frasnian of Poland. Her material has a greater range (1:2—2°8 mm.) 
and a higher mean value (1-8 mm.) for the tabularium diameter than the English 
representatives. There is no doubt that the two samples are conspecific, however, 
and the slight size difference may be due to the higher stratigraphical level of the 
Polish collection. 

Attention is drawn for the first time to the rare horseshoe dissepiments developed 
in representatives of this species. Besides the English examples, Schliiter (1881, 
pl. 9, fig. 5) illustrated a specimen as A. pentagona referable to this species from the 
Frasnian of Stolberg, near Aachen (Germany) which also clearly shows occasional 
horseshoes developed against the tabularium junction. 


Frechastraea bowerbanki (Edwards & Haime) 
Plate rz, Fig. 3; Plate 12, Figs. 1-3 


1851 Smithia bowerbanki Edwards & Haime : 423. 

1852 Acervularia seviaca Quenstedt : 664, pl. 60, fig. 3. 

1853 Smithia bowerbanki Edwards & Haime; Edwards & Haime : 241, pl. 55, figs. 2, 2a. 
1879 Acervularia seriaca Quenstedt; Quenstedt : 536, pl. 163, fig. 1. 


254 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


1883 Phillipsastvaea bowerbanki (Edwards & Haime) C. F. Roemer : 391. 
1885 Phillipsastvaea bowerbanki (Edwards & Haime); Frech : 63, pl. 4, figs. 9, 9a, b. 
?1951 Pachyphyllum bowerbanki (Edwards & Haime) Soshkina : 89, pl. 16, figs. 1, 2. 


But not: 
1879 Smithia bowerbanki Edwards & Haime; Quenstedt : 536, pl. 162, fig. 39. 
1953 LPhillipsastvaea bowerbanki (Edwards & Haime); Rdézkowska : 67, pl. 8, figs. 3, 4. 


Diacnosis. Thamnasterioid Frechastraea. Mean tabularium diameter 1-54 mm. 
with 7 to 12 major septa (East Ogwell sample). Septa rarely slightly dilated at 
tabularium boundary. Dissepiments characteristically weakly arched and rather 
elongate; flattened horseshoes extremely rare. Tabularium structure simple. 


LECTOTYPE. Selected by Soshkina (1951 : 89). The original of Edwards & 
Haime’s (1853, pl. 55), figs. 2, 2a. Devonian; Torquay, south Devon. This speci- 
men appears to be lost. 


MATERIAL. Ramsleigh Quarry: TM(JB)294a (Colony 1), TM136/7 (Colony 2). 
Other measured specimens: BM(NH) R46372-73. 


DISTRIBUTION. England: Lower Frasnian limestones, Ramsleigh Quarry, East 
Ogwell, near Newton Abbot, south Devon. Also Frasnian of Germany (Harz) and 
? the U.S.S.R. (southern Urals). 


DESCRIPTION. The material is fragmentary and nothing is known of the external 
features, shape and overall size of the corallum. 

The colony is thamnasterioid, with the septa of adjacent corallites most commonly 
perfectly confluent and less frequently irregularly abutting. Occasional septa may 
have free ends in the dissepimentarium. The tabularia are regularly and fairly 
widely spaced. 

The septa are 0-05—0-I mm. thick and are regularly developed between tabularia. 
They may be straight, but are usually sinuous and occasionally geniculate. In some 
cases, the sides of the septa are slightly corrugated, presumably by the presence of 
slightly swollen trabeculae; they are never truly carinate and usually the septa are 
smooth sided. Septal dilatation at the tabularium boundary is slight or lacking. 
Usually the major septa project into the tabularium for between o-1r and 0-2 mm. 
with no change in thickness. At this point, they thin abruptly and continue towards 
the axis as strongly attenuate filaments. Occasionally the major septa reach the 
axis but more commonly, they either curve sharply to become confluent with an 
adjacent or nearby septum, or they end about a third of the tabularium radius short 
of the axis. The minor septa end at the tabularium junction. 

The dissepiments are uniserial between adjacent septa. The tabularium junction 
is strongly and sharply defined. 

In longitudinal-section, the dissepimentarium is composed of several series of 
elongate, weakly arched vesicles. The dissepiments are very uniformly developed 
with a height of o-r mm. The surface of the dissepimentarium is flat peripherally, 
rising slightly to a crest just outside the tabularium junction. Rarely a flattened 
horseshoe dissepiment may occur among the series forming the crest, whilst on the 
tabularium side, a vertically discontinuous row of normal dissepiments slopes steeply 
axially and downwards. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 255 


50 


40 


30 


20 


dt (mm) 


Total sample Colony 1 


Colony 2 


Fic. 19. Frechastraea bowerbanki. 


256 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


TABLE 12.—Statistical data for some characters of Frechastvaea bowerbanki. 


Total sample Colony I Colony 2 
N 137 (4) 48 60 
O.R. I+3-1°8 I-3-1°8 I°3-1°8 
X +54 1-54 1+54 
dt Ss 0-12 0:13 0-10 
C.V 7°73 8-65 6:56 
S.E.n 0-010 0-019 0-013 
O.R 7-12 8-11 7-12 
X 9°54 9°65 9°62 
n Ss 0°25 0:42 0:37 
C.V. 2°59 4°31 3:89 
S.E.n 0-021 0:060 0-048 
O.R. 4°71-7:69 5° 00-7:14 5: 00-7-14 
x 6:24 6-30 6:36 
n/dt s 0-34 0-32 0:26 
C.V. 5°48 5:06 4°09 
S.E.n 0-029 0-046 0-034 
Graphs :— 
r 0:89 0:86 0:86 
n/dt a 2:08 3°13 3°70 
b 6°34 4°84 3°91 
n/dt r —0-99 —9°@)5 SOE] 
dt a —2:88 —2:40 —2°57 
b 10:66 9:99 10-32 
A At At/A Graph:—At/A 
O.R. 0:29-0:38 0:016—-0-:020 0°050—-0:057 
x 0:34 0-018 0:054 r 0:96 
s 0-043 0-0015 00033 a 0-036 
C.V. 12°56 8-34 6°13 b 0: 0062 
S.E.m 0-021 0:00077 0:0017 


Tabularium structure is simple and is formed with both complete and incomplete 
tabulae. The complete plates are saucer-shaped, whilst the incomplete plates are 
flat to slightly arched vesicles, horizontally disposed in the centre of the tabularium 
and sloping steeply downwards periaxially. The vertical spacing of the tabulae 
varies considerably between 0-05 and 0:3 mm. 

Increase is lateral, with the daughter corallites developing in the dissepimental 
tissue equidistant from the surrounding adult tabularia. 

Only four incomplete colonies from Ramsleigh Quarry were available for analysis, 
two of which have been selected for individual treatment. The statistics are listed 
in Table r2 and illustrated graphically in Text-figs. 16 and Ig. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 257 


Discussion. Although the lectotype is lost, there can be no doubt from Edwards 
& Haime’s (1853 : 241, pl. 55, figs. 2, 2a) description and figures, of the interpretation 
of this species. Figure 2a shows clearly the distinctive characters in cross-section 
which have been described in the present material. Furthermore, they state 
(1853 : 242) that the diameter of the ‘ wall’ (= tabularium diameter) is about 
two-thirds of a line, which is approximately I-'¢mm. This agrees with the present 
observations but contrasts with the measurements given by Rdzkowska (1953 : 67) 
for her Phillipsastraea bowerbanki. R6zkowska’s specimen is, in fact, distinct from 
the present species and belongs to Frechastraea pentagona minima (see p. 240). 

Quenstedt (1852 : 664, pl. 60, fig. 3) erected a new species, Acervularia seriaca, 
which from his figure and description appears to be conspecific with F. bowerbankt. 
Frech (1885 : 63) was of the same opinion and placed Quenstedt’s species in the 
synonymy for his Phillipsastrea bowerbank1. Later Quenstedt (1879 : 536, pl. 163, 
fig. 1) refigured Acervularia seriaca and in the same work (p. 536, pl. 162, fig. 39) 
also described and figured ‘Smuthia bowerbanki Edwards and Haime’. On the 
evidence of the figures, the specimen of Acervularia seriaca appears, as before, to 
belong to the present species, whilst his Smthia bowerbanki is probably referable to 
F.. pentagona minima. 

F. bowerbanki differs greatly from the species of Frechastraea described above. 
This species has tabularia corresponding in size to those of F. goldfussi but the number 
of septa at any given diameter is strikingly lower in the former. F. bowerbanki also 
occupies a distinctive position on the graph of tabularium area plotted against 
corallite area, reflecting the relatively wide spacing of the tabularia (Text-fig. 16, 
Table Io). 

F.. bowerbankz is further distinguished by its thamnasterioid form and particularly 
by weakly arched, rather elongate dissepiments in contrast to the globose dissepiments 
usually found in species of Frechastraea. 


Genus THAMNOPHYLLUM Pencecke 1894 


1894 Thamnophylium Penecke : 563. 
1909 Phacellophyllum Girich : 102. 
1935 Disphyllum {Phacellophyllum}; Lang & Smith : 546. 
1935 Thamnophyllum; Lang & Smith : 563. 
1939 Disphyllum {Phacellophyllum}; Hill : 224. 
1939 Thamnophyllum; Hill : 227. 

partim 1940 Thamnophyllum; Hill : 260. 
1940 Phacelophyllum; Lang, Smith & Thomas : 98. 
1940 Thamnophyllum; Lang, Smith & Thomas : 133. 
1949 Phacelophyllum; Stumm : 36. 
1949 Thamnophyllum; Stumm : 36. 

partim 1949 Macgeea (Thamnophyllum); Schouppé : too. 
1949 Thamnophyllum; Soshkina : 77. 

partim 1950 Phacellophyllum (Phacellophyllum); Wang : 219. 
1950 Phacellophyllum (Thamnophyllum); Wang : 219. 
1951 Disphyllum {Phacellophyllum}; Taylor : 185. 
1951 Thamnophyllum; Soshkina : 74. 
1952 Thamnophyllum; Soshkina : 85. 


258 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


1953 Thamnophyllum; Rézkowska : 13. 
partim 1953 Macgeea; Rézkowska : 18. 
1954a Phacellophyllum; Hill : 26. 
1954 Thamnophylium; Soshkina : 65. 
1956 Thamnophyllum; Rézkowska : 304. 
1956a Macgeea (Thamnophyllum) ; Fliigel : 48. 
partim 1956a Macgeea (Macgeea); Fligel : 53. 
1956b Macgeea (Thamnophyllum) ; Fliigel : 361. 
partim 1956b Macgeea (Macgeea); Fliigel : 361. 
1956 Thamnophyllum; Hill : 281. 
1956 Phacellophyllum; Hill : 282. 
1957 Thamnophyllum; Rézkowska : 83. 
1958 Macgeea (Thamnophyllum) ; Fliigel : 625. 
1958 Macgeea ([Thamnophylium) ; Schouppé : 226. 
1959 Thamnophyllum; Fligel : 115. 
partim 1959 Phacellophyllum; McLaren : 28, 
1960 Thamnophyllum; Rézkowska : 44. 
partim 1963 Macgeea (Macgeea); Schouppé & Stacul : 288. 
1963 Macgeea (Thamnophyllum) ; Schouppé & Stacul : 291. 
1964 Thamnophyllum; Webby : 9. 


DiaGnosis. Dendroid or phaceloid rugose corals with axial and in one species, 
lateral increase. Septa of two orders, usually spindle-shaped in dissepimentarium. 
Dissepimentarium typically with outer series of flat dissepiments and inner series of 
horseshoe dissepiments. In some species, dissepimental structure obscured by stereo- 
plasmic thickening. Tabulae complete or incomplete, with periaxial plates variably 
developed. 


TYPE SPECIES. Selected by Lang & Smith (1935 : 564) and see Fliigel (1958 : 625). 
Thamnophyllum stacher Penecke 1894 : 594, pl. 8, figs. I-3; pl. 11, figs.1,2. Emsian 
(barrandei-Schichten); Marmorbruch am Graz, Austria. 


DISTRIBUTION. Lower to Upper Devonian of Europe, Asia, Australia and North 
America. 


Discussion. Penecke (1894 : 563) described four species of Thamnophyllum, three 
of them new and the other T. trigeminum (Quenstedt) (see T. germanicum germanicum 
nom. nov., p. 260). From these, Lang & Smith (1935 : 564) selected T. stachet as 
type species and redescribed this and Penecke’s other species. They removed T. 
trigemmnum from Thamnophyllum and assigned it to Phacellophyllum Giirich, which 
they regarded as a genomorph of Disphyllum. Girich (1909 : 102) had placed 
only ‘ Phacellophyllum caespitosum Goldf.’ in his new genus. As Lang & Smith 
(1935 : 547) pointed out, Giirich’s figures (1909, pl. 31, figs. 5a, 6) were copied from 
Schliiter (1881, pl. 9, figs. 6, 7) which fixes the type species of Phacellophyllum as 
Lithodendron caespitosum Goldfuss. 

Schouppé (1949), in a detailed consideration of species of Thamnophyllum and 
Phacellophyllum, was the first to place the latter in synonymy with the former. 
Furthermore, he made Thamnophyllum a subgenus of Macgeea on the basis of their 
similar structural plan, separating M. (Thamnophyllum) and M. (Macgeea) principally 
on their growth form. 

Both Soshkina (1951, 1952, 1954) and Rdzkowska (1953, 1956, 1957, 1960) followed 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 259 


Schouppé in considering Phacellophyllum as synonymous with Thamnophyllum, but 
neither supported the subgeneric relationship with Macgeea: Rozkowska (1953 : 18, 
1957 : 102) listed the characters by which Macgeea and Thamnophyllum may be 
distinguished. On the other hand, Hill (1954a@, 1956) and McLaren (1959) retained 
Thamnophyllum and Phacellophyllum as separate genera. McLaren (1959 : 28) 
pointed out that T. stachei, type species of Thamnophyllum, is imperfectly known, 
whereas Phacellophyllum has adequately described type material. From Lang & 
Smith’s (1935) descriptions, he regarded the synonymy of the two genera as by no 
means certain. 

The development of periaxial tabulae in the type species of Phacellophyllum has 
led to an involved and lengthy exchange on the taxonomic position of this genus in 
recent years between Fliigel and Schouppé. Fliigel (1956a : 53, 1965) : 361), 
describing the peripheral plates in the tabularium of Lithodendron caespitosum as a 
third zone of normal dissepiments, compared the structure of the species in longitu- 
dinal-section with that developed in typical forms of Macgeea. On this basis, he 
placed Phacellophyllum in synonymy with Macgeea sensu stricto and retained Thamno- 
phyllum as a subgenus of Macgeea characterized by only two zones of dissepiments, 
flat and horseshoe. Schouppé (1958 : 220 e¢ seq.) rejected this classification. He 
considered the ‘third dissepimental zone’ to constitute part of the tabularium 
structure and stated (p. 227) that no sharp line could be drawn between the develop- 
ment of periaxial tabulae in Macgeea and Thamnophyllum. Schouppé thus retained 
his 1949 classification, placing Phacellophyllum in Thamnophyllum, which he separated 
subgenerically from Macgeea on the basis of their contrasting growth form and grade 
of general structural complexity. Fliigel (1959 : 115, footnote) later criticized 
Schouppé’s (1958) subgeneric diagnoses as insufficiently differentiated. Nevertheless, 
he subscribed to a very similar classification, that of R6zkowska (1957), considering 
not only Phacellophyllum to be synonymous with Thamnophyllum, but the latter 
to be generically distinct from Macgeea. Finally, Schouppé & Stacul (1963) published 
a detailed consideration of the genera involved, in which they returned almost exactly 
to the position held by Fliigel (1956). They wrote (1963 : 285) that ‘... the princi- 
pal stress in the systematic classification should be laid on the appearance of vesicular 
elements in the peripheral area of the tabularium. Consequently, all those forms 
having peripheral vesicles in the tabularium (even if only sporadic...) must be 
placed in Macgeea (Macgeea). Forms with, on the other hand, simple, peripheral, 
*‘split-open’ tabulae or additional periaxial, sloping, plate-like elements—without 
peripheral vesicles—belong to Macgeea (Thamnophyllum).’ Thus they placed 
Phacellophyllum in synonymy with Macgeea (Macgeea). 

In the writer’s opinion, Phacellophyllum is a junior synonym of Thamnophyllum 
and the latter is generically distinct from Macgeea. The periaxial elements, so 
conspicuous in some specimens of Lithodendron caespitosum may show considerable 
variation in their development within the species as a whole (see p. 268). Further- 
more, they occur to a greater or lesser degree in many other species of Thamnophyllum. 
It seems unreasonable to suggest a morphological and genetic distinction between 
the periaxial elements developed in Phacellophyllum and Thamnophyllum at what 
must be considered an arbitrary level in their degree of structural complexity. Such 


260 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


a variable character cannot be used as the basis of a subgeneric division, especially 
as it cuts across the more obvious distinction in growth form. Species of Macgeea 
are simple, conical corals which only rarely show budding. In a collection of 234 
individuals belonging to six species and subspecies, R6zkowska (1957 : 118) found 
only four budding specimens. Thamnophyllum and Phacellophyllum, on the other 
hand, are phaceloid or dendroid forms with cylindrical corallites. Commonly in 
Macgeea, the horseshoe dissepiments are less regular in form and superposition with 
a generally more complex tabularium and dissepimentarium structure. In addition, 
Macgeea usually shows distinct bilateral symmetry in the adult stage in contrast to 
the radial symmetry of Thamnophyllum and Phacellophyllum. 

As McLaren (1959 : 28) remarked, existing knowledge of T. stachei is rather imper- 
fect, but the writer believes enough is known from the work of Lang & Smith (1935 : 
581) to permit an opinion on the taxonomic status of Thamnophyllum. T. stachei, 
from Penecke’s figures, Lang & Smith’s description and their specimens (BM(NH) 
R30990-94), shows evidence of all the characteristic features described in better 
known species of Thamnophyllum. As R6zkowska (1957 : 101) stated, it is a primi- 
tive early member of the genus in which the tabulae are very simple and widely 
spaced. Stereoplasmic thickening, which in 7. stachei almost completely obscures 
the dissepimental structure, is also a variable factor in other species of Thamnophyllum. 


Thamnophyllum germanicum germanicum nom. nov. 


1894 Thamnophyllum trigeminum (Quenstedt) Penecke : 596, pl. 8, figs. 4-6. 
1959 Thamnophyllum tnigeminum trigeminum Penecke; Fliigel : 117 (see for extensive syno- 


nymy). 

1960 Thamnophyllum trigeminum trigeminum Penecke; Rdzkowska : 53. 

1963 Macgeea (Thamnophyllum) trigemina trigemina (Penecke) Schouppé & Stacul, text-figs. 5, 
?r9. 

1963 Macgeea (Macgeea) sp. Schouppé & Stacul, text-fig. 18. 


But not: 
1879 Cyathophyllum caespitosum trigemme Quenstedt : 518, pl. 162, figs. 5-8. 


DiaGnosis. See R6zkowska (1956 : 310). 


LECTOTYPE. Selected by Fliigel (1959 : 118). UPG 8gr (Collections of the 
Paladontologisches Institut, Graz) labelled by Penecke in 1892 as “ Fascicularia 
trigemina’”’. Givetian; (?) Auberg, near Gerolstein, Eifel, Germany. 


DESCRIPTION. See R6zkowska (1956 : 310). 


Discussion. Cyathophyllum caespitosum trigemme Quenstedt has been shown by 
Fliigel (1959) to belong to Favistella (Dendrostella). Hitherto it had been regarded 
as a species of Thamnophyllum, largely due to Penecke (1894 : 596) misinterpreting 
Quenstedt’s description and illustrating as Thamnophyllum trigeminum (Quenstedt) 
a new and generically different species. Subsequent workers had relied mainly on 
Penecke’s work for the identification of Quenstedt’s subspecies. 

Fliigel (1959 : 117) thus described Penecke’s material as Thamnophyllum trige- 
minum trigeminum Penecke. The retention of Quenstedt’s specific name for Penecke’s 
misidentified material, however, is not in accordance with Article 49 of the I.C.Z.N. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 261 


(1964) and a new name is required. With the permission of Professor Fliigel, 
Thamnophyllum trigeminum trigenunum Penecke is hereby renamed Thamnophyllum 
germanicum germanicum nom. nov. after the country of origin of Penecke’s specimens. 


Thamnophyllum germanicum schouppei nom. nov. 
Plate 13, figs. 1-4; Plate 14, figs. 1-4 


1949 Macgeea (Thamnophyllum) caespitosa (Goldfuss) var. minus (F. A. Roemer) Schouppé : 152 
pars, pl. Io, figs. 21-24; pl. 13, figs. 73-75 (non pl. 11, figs. 38-39; pl. 13, figs. 76-77; 
pl. 14, figs. 100a-c). 

1956b Macgeea ([Thamnophyllum) minima Schouppé, Fliigel : 361. 

1965 Thamnophyllum cf. trigeminum Penecke; Scrutton : 186. 

But not: 

1855 Diphyphyllum minus F. A. Roemer : 29, pl. 6, figs. 12a-c. 


Diacnosis. Thamnophyllum with mean corallite diameter 4:2 mm. and 12 to 20 
major septa (topotype sample). Axial increase with three or four buds lacking 
caenogenetic tissue in axils of branches. Tabulae complete or incomplete with 
periaxial plates sporadically developed. Skeletal elements generally unthickened. 


HototypPe. See Fltigel (1956) : 361). UGP327 (Collections of the Palaonto- 
logisch Institut, Graz). The specimen is labelled “Middle Devonian, Torquay ”’ 
only, but it comes without doubt from the Givetian limestones in Dyer’s Quarry. 


MATERIAL. Dyer’s Quarry: OUM D506 (Colony 1), OUM D507 (Colony 2), 
OUM D508 (Colony 3). Other measured material: OUM D271, OUM D509, OUM 
D511. Additional material: OUM D272, OUM D504-5, OUM Dsro. 


DISTRIBUTION. Type locality only. 


DESCRIPTION. Colonies are phaceloid, up to 100 cm. in diameter, consisting of 
close-spaced, sub-parallel, cylindrical corallites. External features are unknown as 
recent weathering has removed the epitheca to expose the peripheral ends of the 
septa. Calices have not been observed. 


In cross-section the corallites are circular to sub-circular. The epitheca, normally 
about o-r mm. thick, is frequently preserved within the matrix. The septa, of two 
orders, are slightly spindle-shaped in the dissepimentarium. The minor septa may 
or may not penetrate very slightly into the tabularium but the major septa usually 
reach a half to two-thirds the distance to the axis. The septa are normally straight 
in the dissepimentarium but the major septa often become slightly curved or sinuous 
in the tabularium. 

The traces of the sides of the horseshoe dissepiments form a distinctive double wall 
in cross-section. Between adjacent septa, the two walls are convex towards each 
other, reflecting the saddle-shaped form of the horseshoe dissepiments. They are, 
on average, about 0-4 mm. apart, with the outer wall the same distance from the 
epitheca. The innermost wall is the boundary between the dissepimentarium and 
the tabularium. 

GEOL. I5, 5- 26 


262 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


50 
40 
30 
f 
20 
a 
10 ee ON 
— uf OM ie 
GE is 
6 y a A, . 
“SS 
(0) n/ | 1 ' 1 1 7 i 
D5) 3:15 3:95 475 S}5)5) 


d (0:4mm class intervals) 


dt 


(mm) 


n 
ny 
A 
4 5 6 7118 
d (1mm class intervals) 
3:0 40 5-0 60 
d_ (mm) T. g. schouppei I. g. skalense 
Total sample Colony 1 Colony 2 Colony 3 IT. g. germanicum T. g. pajchelae 


Fic. 20. Thamnophyllum germanicum schoupper. Inset: Graphical comparison of some 
quantitative characters for the subspecies of Thamnophyllum germanicum. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 263 


In longitudinal-section, the dissepimentarium is composed of an outer series of 
flat plates and an inner series of horseshoe dissepiments. The outer plates are not 
always seen as they are easily removed by erosion. They are slightly irregular in 
spacing, usually between 0-2 and 0-5 mm. apart and always uniserial. They may 
be perfectly flat, slightly concave or convex. The horseshoe dissepiments are thin 
walled and regularly developed in a single series, normally between three and four 
to I mm. 

The tabulae are complete or incomplete, often with irregularly developed periaxial 
plates. They may be flat or slightly bowed or arched, and sometimes strongly 
convex towards the calice. Tabulae in the form of flat-topped domes are rare. 
The spacing of the tabulae is variable but averages about 18 to I cm. 

Increase is exclusively axial with three or four daughter corallites produced in 
each case. There is no indication of extra-dissepimental tissue (caenogenetic tissue 
of Soshkina 1953) between the newly formed buds. As soon as normal dissepimental 
tissue begins to form in the axial area of the parent corallite, the daughter corallites 
become phaceloid. 

Increase is often seen in hand specimen but it is difficult to assess quantitatively 
the frequency with which it occurs. On one specimen, OUM D508/4, three newly 
formed corallites were seen to bud themselves. The increments of vertical growth 
between formation and budding in these cases measured I-3 cm., I-4 cm. and I-7 cm. 
Also the corallite diameters at which budding may occur are usually indeterminate 
as it is very rare to obtain a cross-section at the inception of blastogeny when it is 
still possible to measure the diameter of the parent corallite. 

A statistical analysis has been made of a total sample comprising six colonies from 
Dyer’s quarry. Three of these colonies have also been analysed individually. The 
statistics are listed in Table 13 and illustrated graphically in Text-fig. 20. 

Discussion. Specimen UPG327 was first described, with some other material, 
as Macgeea (Thamnophyllum) caespitosa var. minus (F. A. Roemer) by Schouppé 
(1949 : 152). Both Fligel (19655 (August) : 361) and Schouppé (1956 (September) : 
153, footnote) noted that the Torquay specimen was not in fact conspecific with 
Roemer’s species and Fliigel suggested that, as a species in its own right, it should 
be called Macgeea (Thamnophyllum) minima Schouppé. Under article 49 (Article 
70b does not apply here) of the I.C.Z.N. (1964), however, Fliigel’s use of Roemer’s 
specific name for Schouppé’s misidentified material is invalid and a new name is 
needed. With the permission of Professors A. von Schouppéand H. Fliigel, ““ Macgeea 
(Thamnophyllum) minima Schouppé ”’ is hereby renamed, as a subspecies of Thamno- 
phyllum germamcum, T. germanicum schouppei nom. nov. 

In his original description, Schouppé (1949 : 155) stated that ‘ The budding is 
lateral and not parricidal (= axial) ’ in Macgeea (Thamnophyllum) caespitosum var. 
minus. This is certainly true of Roemer’s species and Schouppé’s remark must have 
been based on correctly identified material. The holotype, in fact, gives no clear 
indication of its style of increase, although the evidence from topotypic material of 
the present subspecies shows that it must be axial. 

Thamnophyllum germanicum schouppei is closest in general characteristics to the 
other subspecies of T. germanicum described from the Middle Devonian—T. ger- 

GEOL. I5, 5- 26§ 


264 COLONIAL PHILLIPSASTRAEIDAE PROM S2E. DEVON 


manicum germanicum nom. nov., T. germanicum skalense (R6zkowska) and T. 


germanicum pajchelae (R6zkowska) (see R6zkowska 1960 : 53). 


As Rodzkowska 


(1956) gave data on corallite diameter and number of major septa for the latter three 
subspecies, it is possible to compare them statistically with the present material 


TABLE 13.—Statistical data for some characters of Thamnophyllum germanicum schouppet. 


dt 


dt/d 


n/d 


Graphs :— 


dt/d 


n/d 


n/d 
d 


Total sample 


N 153 
O.R. 2°9-5'7 
x 4°19 
Ss @)° Si) 
c.V. 14°08 
S.E.m 0-048 
O.R. 1°7-3°7 
X 2+69 
s 0-40 
c.V. 14°79 
S.E.n 0:032 
O.R. 0+55-0:70 
X 0:64 
Ss 0-016 
C.V. 2°43 
S.E.n 0:0013 
O.R. 12-20 
x 16°52 
Ss OY) 
C.V. 7°41 
S.E.n 0+099 
O.R 3:08-5:16 
x 3:98 
Ss 0:30 
C.V. 7°51 
S.E.n 0-024 
r 0-99 
a 0-68 
b —O'l4 
r 0-90 
a 2:08 
b 7°83 
r —0'94 
a —0O'5I 
b 6-11 


Colony 1 


0*59-0:70 
0-64 
0:023 
3°63 
00048 


13-18 
15°91 
I +24 
WUE 
0:26 


BAe ROO 
4°07 
0:29 
7:00 
0:059 


0:96 
0°73 
— 0°34 


0:85 
2°45 
6:26 


—o:84 
—0:56 
6:29 


Colony 2 
50 


305552 
4°00 
0-56 
13°98 

0-079 


1:8-3:'1 
2°53 
0:36 
14°18 

0-051 


0:55-0:65 
0-63 
0:020 
3°09 
0-0028 


12-20 
16-14 
I-51 
9735 
0-21 


3°46-5-16 
4:06 


(ol 
772 
oO: 


° 
Ne) 
(ee) 


—0:036 


—o-78 
—o-56 


Colony 3 
46 


fo} 
Ne} 
(oe) 


—0094 


ie) 
“N 
4 


=O) 5Y7/ 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 205 


(Table 14 and Text-fig. 20). Only T. gerymanicum pajchelae proved not to be signifi- 
cantly different from T. germanicum schouppei in the frequency distribution of their 
corallite diameters. When septal number was plotted against corallite diameter, 
however, the lines of all three subspecies were found to be significantly different from 
that for T. germanicum schouppet. 

Qualitatively, the latter differs from the other three subspecies by the absence of 
caenogenetic tissue between newly formed buds. T. germanicum skalense also 
differs through the excessive thickening of its septa in the zone of horseshoe dissepi- 
ments and 7. germanicum pajchelae is remarkable for its regular and widely spaced 
complete tabulae and general simplification of its internal structure. 

T. germanicum schoupper differs markedly from the Frasnian subspecies of Thamno- 
phyllum germamcum, T. germanicum kozlowsku (R6zkowska) and T. germanicum 
superius (Rdzkowska) (see R6zkowska 1960 : 53), through the larger dimensions of 
the latter pair. The mean corallite diameters of the Frasnian subspecies (R6zkowska 
1957 : 93 as T. kozlowsku and T. kozlowskit superius) are 10-03 and 9:28 mm. respec- 
tively. In addition, T. germanicum kozlowsku is characterized by a more complex 
dissepimentarium than typical thamnophyllids, with one or two series of horseshoe 
dissepiments, and the tabularium has highly developed periaxial elements. In the 
writer’s opinion, this form deserves full specific rank. T. germanicum supertus, 


TABLE 14.—Statistical discrimination between some characters of Thamnophyllum germanicum 
subspecies and T. gerymanicum schouppet. Significant values in bold. 


schoupper  pajchelae skalense geymanicum 
N 153 73 69 107 
O.R. 3-6 2-7 2-8 3-10 
x 4°14 4°II GPSS) 7°00 
d s 0-62 I-13 1°52 1°39 
C.V. I5:O1 27°37 28-42 20:81 
S.E.m 0-050 0°13 0:18 0:13 
“t” test against schouppei :— 
t 0-29 8-46 22-45 
O.R 12-20 12-25 10-27 16-29 
x 16°53 16-90 20-01 23°25 
n Ss I-06 2:81 B20 2°34 
C.V. 6°43 16:60 16-04 10:07 
S.E.n 0-086 0:33 0-39 0:23 
Graph :— 
r 97 0:99 0:98 I-00 
n/d a I-71 2°49 QT 69 
b 45 6:65 8-72 11°43 


“7” test against schouppet :— 


z (slope) 13-07 6-00 0:58 
Z (position) 19-07 


266 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


described originally as T. monozonatum Soshkina by Rozkowska (1953 : 14), differs 
from T. germanicum schouppet by the possession of complete, concave tabulae more 
reminiscent of 7. hornesi Penecke (as noted by Rdzkowska) than the T. germanicum 
group. 

T. germanicum schouppet is closely similar in most respects to T. caespitosum 
(Goldfuss). The latter, however, has exclusively lateral increase in contrast to the 
axial increase of the former. 


Thamnophyllum caespitosum (Goldfuss) sensu lato 
Plate 15, figs. 2-4; Plate 16, figs. 1, 2 


1826 Lithodendron caespitosum Goldfuss : 44, pl. 13, fig. 4. 

1848 Cladocova antiqua Bronn : 303. 

1851 Lithostrotion antiquum (Bronn) Edwards & Haime : 439. 

1879 Cyathophyllum caespitosum Goldfuss; Quenstedt : 509 pars. 

1881 Fascicularia caespitosa (Goldfuss) Schliiter : 103, pl. 9, figs. 6, 7. 

1885 Cyathophyllum caespitosum Goldfuss; Frech: 33 pars. 

1909 Phacellophyllum caespitosum (Goldfuss) Giirich : 102 pars, pl. 31, fig. 5. 

1935 Disphyllum {Phacellophyllum} caespitosum (Goldfuss) Lang & Smith : 573, pars, text- 
figs. 28, 20, pl. 35, figs. 1, 2. 

1949 Macgeea (Ihamnophyllum) caespitosa (Goldfuss) Schouppé : 138, pl. 9, fig. 3, pl. 11, 
figs. 40-43. 

1949 Phacelophyllum caespitosum (Goldfuss); Stumm : 36, pl. 17, figs. 11-13. 

1951 Disphyllum {Phacellophyllum} caespitosum (Goldfuss); Taylor : 186, pl. 3, figs. 3a, b, 
non figs. 4a, b. 

1956 Thamnophyllum caespitosum (Goldfuss); Rézkowska : 308, text-figs. 30-32. 

1956a Macgeea (Macgeea) caespitosa (Goldfuss) Fligel : 54. 

1956b Macgeea (Macgeea) caespitosa (Goldfuss); Fliigel : 361. 

1957 Thamnophyllum caespitosum (Goldfuss); Rézkowska : 89, text-fig. 8. 

1958 Macgeea (Thamnophyllum) caespitosum (Goldfuss); Schouppé : 227, text-figs. 7-9. 

1963 Macgeea (Macgeea) caespitosa (Goldfuss); Schouppé & Stacul : 268, text-figs. 4, 17. 

1964 Thamnophyllum caespitosum (Goldfuss); Webby : 9, text-figs. 3a—d. 


But not: 
1826 Cyathophyllum caespitosum Goldfuss : 60, pl. 19, figs. 2a—d. 
1956 Phacellophyllum caespitosum (Goldfuss); Hill : 282, text-fig. 192 (6). 


Dracnosis. Phaceloid Thamnophyllum. Mean tabularium diameter 6-17 mm. 
with 18 to 22 major septa (Wolborough Quarry sample). Major and minor septa 
slightly dilated in zone of horseshoe dissepiments. Dissepimentarium regularly 
developed with single outer series of horizontal plates and single inner series of 
horseshoe dissepiments with slightly thickened sides. Tabularium structure highly 
variable from closely spaced flat-topped domes with inosculating periaxial tabulae 
to complete, sagging plates, well spaced and with rare subsidiary plates. Increase 
lateral. 

LECTOTYPE (selected by Lang & Smith 1935 : 573). Original of Goldfuss 1826, 
pl. 13, fig. 4 (Goldfuss Collection, Geologisch-Paldontologisches Institut, Bonn). 
Givetian; Bensberg, near K6ln, Germany. 


MATERIAL. BM(NH) R46167-75; middle Givetian limestones, Wolborough 
Quarry, Newton Abbot, south Devon. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 267 


DisTRIBUTION. England: middle and upper Givetian of the Ilfracombe Beds, 
north Devon and west Somerset; Givetian limestones, Plymouth; middle Givetian 
limestones of Wolborough Quarry, Newton Abbot, south Devon. Also common in 
the Givetian of Europe. 


DESCRIPTION. Colonies with well spaced, cylindrical corallites. External features 
and colony shape unknown as the material is fragmented and embedded in a hard, 
limestone matrix. 

In cross-section, the corallites are circular to sub-circular. The epitheca, which is 
rarely preserved in the matrix, is about 0:05 mm. thick. Major and minor septa are 
slightly and evenly dilated to o-r mm. thickness for a length of I-1-25 mm. across 
the zone of horseshoe dissepiments. The minor septa appear to penetrate slightly 
into the tabularium whilst the major septa, thin and often slightly sinuous, continue 
towards the axis. The latter are a half to two-thirds the corallite radius in length. 

The traces of the horseshoe dissepiments form two strong internal walls, convex 
towards each other, in cross-section. 

In longitudinal-section, the dissepimentarium comprises an outer series of hori- 
zontal plates and an inner series of horseshoe dissepiments, their respective widths 
in the ratio 1 : 1-3. The plates of the outer series may be flat or very slightly curved 
and are exclusively uniserial. Their spacing varies between 0:25 mm. and 0-65 mm. 
The horseshoe dissepiments are also exclusively uniserial and fairly uniform in size 
and shape. They average 0-3 mm. high. The crest of each horseshoe is thin but 
the sides are moderately and evenly thickened up to 0-or mm. 

The axial tabulae are complete or incomplete, usually closely spaced and arched 
with a wide flat crest. Periaxial elements are usually well developed as small 
arched plates inosculating with the main tabulae. Tabularium structure is, however, 
very variable and includes corallites with wide flat tabulae with scattered periaxial 
plates and rarely, well spaced, dominantly complete, saucer-shaped tabulae. The 
vertical spacing of plates in the axis of the tabularium varies from 14 per cm. when 
the structure is complex, to Io per cm. when the structure is simple. 

Increase, only observed in a few cases, is lateral with a high angle of divergence 
between parent and bud. 

It was possible to measure only a few corallites accurately so that no attempt has 
been made to analyse the figures in detail. Data obtained are given in Table 150. 


Discussion. See under Thamnophyllum caespitosum paucitabulatum (p. 268). 


Thamnophyllum caespitosum paucitabulatum subsp. nov. 
Plate 15, fig. 1; Plate 16, figs. 3-7; Plate 17, figs. 1-3 
DERIVATION OF NAME. The name, pauci- (paucus L. = few) tabulatum, refers to 
the simple, relatively wide spaced tabulae characteristic of the subspecies. 


Diacnosis. Thamnophyllum caespitosum with tabularium composed of flat, 
slightly arched, or saucer-shaped tabulae with rare periaxial elements. Mean 
tabularium diameter 5-68 mm. with 16 to 21 major septa (Topotype sample). 


268 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


HototypPe. BM(NH) R46165; upper Givetian limestones; Lummaton Quarry, 
Torquay, south Devon. 


MATERIAL. BM(NH) R46160-6. 
DISTRIBUTION. Type locality only. 


DESCRIPTION. Subphaceloid colonies of indeterminate size. Corallites cylindri- 
cal, subparallel and fairly wellspaced. External features are unknown as the material 
is embedded in a hard limestone matrix. 

The structural details are as for Thamnophyllum caespitosum above with the 
following exceptions and additions. 

In longitudinal-section, the tabulae are usually complete. They may be slightly 
arched with wide flat crests, when small arched periaxial elements are poorly 
developed. More commonly, the tabulae are flat or saucer-shaped with very rare 
flat or slightly arched subsidiary plates. There are between 8 and 12 tabulae per 
cm.; spacing of the plates increases from corallites with arched tabulae to those 
with saucer-shaped tabulae. 

Increase is exclusively lateral, occasionally with two offsets developed at the same 
level. A small amount of extradissepimental tissue is always developed between 
the parent and the bud but the angle of divergence is usually high, restricting the 
plocoid stage toa minimum. Measured corallites showing the early stages of increase 
are 6:5 and 6:6 mm. in diameter. 

A statistical analysis has been made of the sample from Lummaton Quarry. 
Individual colonies cannot unfortunately be distinguished. The statistics are listed 
in Table 15a and illustrated graphically in Text-fig. 21a. 


Discussion. Previous descriptions of Thamnophyllum caespitosum (Lang & 
Smith 1935 : 573; Rozkowska 1956 : 308; Webby 1964 : 9) all mention tabularia 
composed of flat or slightly arched tabulae with well developed periaxial elements. 
No great variation in this structure is mentioned. In fact Fliigel (19560 : 361) and 
Schouppé & Stacul (1963 : 268) have placed this species in Macgeea on the basis of 
the complex tabularium structure (see discussion of Thamnophyllum, p. 259). The 
material collected from Wolborough and Lummaton Quarries in south Devon, 
however, shows considerable variation in the shape and distribution of the tabulae. 
The sample from Wolborough has a particularly wide range although the majority 
of the corallites display the tabularium structure considered typical of T. caespitosum 
sensu stricto. At Lummaton, on the other hand, the typical form is not represented 
and in most cases the tabularia have wide spaced flat or saucer-shaped tabulae with 
only rare periaxial elements. Although in other respects the two samples are 
virtually identical, the range in tabularium structure is so striking and, in view of 
the taxonomic weight hitherto placed on this character, so important that the erec- 
tion of a new subspecies, T. caespitosum paucitabulatum, for the Lummaton material 
is felt to be justified. 

T. caespitosum caespitosum is interpreted strictly in terms of the lectotype (see 
Lang & Smith 1935 : 573) and includes the material described by Rézkowska and 
Webby. The highly variable middle Givetian Wolborough material, however, is 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 269 


On 


20 10 
8 
15 
6 
f 10 f 
4 
2 


fo} 
fo} 


3:95 475 5555) 635 715 3:65 445 5:25 605 6°85 
d (0-4 mm class intervals) d (0-4 mm class intervals) 
50 50 
40 40 
dt dt 
(mm) (mm) 
3.0 3:0 
2:0 2:0 
21 22 
1 
20 2 
20 
n 19 n 
19 
18 18 
17 17 
45 50 
40 45 
ny, ny, 
Ya 35 Ya 40 
3:0 3-5 
2:5 3:0 
5:0 60 70 40 5-0 60 
d (mm) d (mm) 
(a) (0) 


Fic. 21. a, Thamnophyllum caespitosum paucitabulatum. b, Peneckiella salternensis. 


270 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


TABLE 15.—a. Statistical data for some characters of Thamnophyllum caespitosum paucitabulatum. 
b. Statistical data for some characters of Thamnophyllum caespitosum (sensu lato). c. Statistical 


dt 


dt/d 


n/d 


Graphs :— 


dt/d 


n/d 


ay A 
d 


data for some characters of Peneckiella salternensis. 


op 4 


(2) (0) 
Total sample 
62 12 
4 . 5-6 S 9 5 
5:68 6-17 
0°55 
9:66 
0-070 


3°0-4°9 
3°79 4°14 
0-40 
10°88 
0-051 


0-62-0°71 
0-65 
0-021 
S927 
0-0027 


16-21 18—22 
18-92 20:00 
O75 

3°95 

0-095 


Ssh) 3°26 


—0o:90 
—0-54 


Total sample 


(c) 
Total sample 


33 
4°0-6°3 


5° 


28 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 271 


assigned to T. caespitosum sensu lato, from which it is thought the upper Givetian 7. 
caespitosum paucitabulatum from Lummaton directly descended. 

Quantitatively, T. caespitosum paucitabulatum has a slightly lower mean corallite 
diameter than that for T. caespitosum sensu lato although the latter has insufficient 
measurements for accurate comparison (Tables 15a, 6). Figures available for T. 
caespitosum caespitosum— close to 6mm.’ corallite diameter with ‘usually 18 
to 19’ major septa (Webby 1963: 10) and ‘corallites average about 6mm. in 
diameter and have about 20 major septa ’ (Ré6zkowska 1956 : 308)—compare closely 
with those for the Wolborough material. Lang & Smith (1953 : 574), however, 
record fewer major septa—16 to 18—with an average corallite diameter of 6 cm. 
(sic) in the lectotype of T. caespitosum caespitosum. 

T. caespitosum is structurally most similar to the T. gerymanicum group but is 
distinguished from it, and all other species of Thamnophyllum, by the possession of 
lateral budding. 


Thamnophyllum spp. 


MATERIAL. BM(NH) R46r81, middle Givetian limestones (see Middleton 1959), 
Shinner’s Bridge Quarry, near Dartington (SX 78906225); BM(NH) Ry 46178, 
Givetian limestones, road cutting immediately south of junction of Babbacombe 
Road with Acre Lane, Torquay (SX 93186477); BM(NH) R46177, Givetian lime- 
stones, disused quarry on Teignmouth Road, Torquay (SX 91126553); BM(NH) 
R46179-80, Middle Devonian (?Givetian) thin bedded limestones, 80 ft. above sea 
level in cliff at northern end of Redgate Beach, Torquay (SX 93516494). All south 
Devon. 

Discussion. These fragments, which do not all belong to the same species or 
subspecies, can nevertheless be placed in either Thamnophyllum caespitosum or T. 
germanicum. Unfortunately none of them gives evidence of the mode of increase 
which is critical in distinguishing between the two species. Further material may 
eventually enable the accurate determination of these specimens. 


Genus PENECKIELLA Soshkina 1939 


partim 1939 Peneckiella Soshkina : 23. 
partim 1939 ©6Disphyllum; Hill : 224. 
partim 1949 Peneckiella; Soshkina : 141. 
partim 1949 + Macgeea (Thamnophyllum); Schouppé : 115. 
partim 1950 Phacellophyllum (Phacellophyllum); Wang : 219. 
partim 1951 Peneckiella; Soshkina : 103. 
partim 1952 Peneckiella; Soshkina : 103. 
partim 1954 Peneckiella; Soshkina : 32. 
partim 1954a Peneckiella; Hill : 25. 
1956 Peneckiella; Schouppé : 153. 
1956a Peneckiella; Fliigel : 55. 
1956b Peneckiella; Fliigel : 355. 
partim 1956 Peneckiella; Hill : 282. 
1958 Peneckiella; Schouppé : 229. 
1959 Acinophyllum McLaren : 22. 


272 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


partim 1959 Phacellophyllum; McLaren : 28. 
1960 Peneckiella; Rézkowska : 29. 
1960 Sudetia Rédzkowska : 35. 

partim 1965 Peneckiella; Strusz : 555. 


DiacGnosis. Phaceloid or dendroid rugose corals. Septa, major and minor, may 
be lightly carinate and dilated in dissepimentarium. Characterized by one or two, 
seldom more, series of dissepiments of variable form but always including peneckiel- 
loid dissepiments. Horseshoe, flat and sigmoidal dissepiments may also be present. 
Tabulae complete or incomplete, frequently with flat-topped domes. Increase 
usually lateral but may be axial. 


TyPE SPECIES. Diphyphyllum minus F. A. Roemer (1855 : 29, pl. 6, figs. 12a-c). 
Frasnian, Ibergerkalk; Winterberg near Bad Grund, Harz, Germany. 


DISTRIBUTION. Uppermost Givetian and Frasnian of Europe; ?upper Lower 
Devonian to Frasnian of Australia; ?Lower, Middle and Upper Devonian of North 
America. 


Discussion. In her original diagnosis, Soshkina (1939 : 23) included ‘ simple or 
composite, fasciculate and massive’ corals and described the dissepimentarium as 
composed of ‘one row of regularly spaced vesicles... sometimes flattened from 
above’. Soshkina (1954 : 32) later gave a slightly different diagnosis for the genus 
which Fliigel (19560 : 355) mistranslated as excluding massive forms from Peneckiella. 
Schouppé (1958 : 191) pointed out Fligel’s mistake but himself concluded that 
Peneckiella should be correctly defined (1958 : 192) as excluding massive forms. 
Both Fligel (1956b) and Schouppé (1958) gave extended discussions of this genus 
and concluded that it is characterised basically by a single, rarely double row of 
horseshoe dissepiments only in the dissepimentarium. 

It is clear, however, from the holotype of Peneckiella minor, type species of 
Peneckiella, that it is peneckielloid (see R6zkowska 1960 : 32) and not true horseshoe 
dissepiments that are characteristic of the genus. No true horseshoe dissepiments can 
be positively identified in the holotype (Plate 17, figs. 4, 5), although they do occur 
in a subsidiary role in the dissepimentaria of some topotype specimens. 

McLaren (1959 : 22) in the discussion of his new genus Acinophyllum, remarked 
that, from Frech’s (1885 : 34, pl. I, figs. 3, 3a, 3b) account of Cyathophyllum minus 
(F. A. Roemer), which was based on Roemer’s specimen, ‘it would appear likely 
that Acinophyllum simcoense is congeneric with Diphyphyllum minus and therefore 
with Peneckiella. But D. minus has been described several times since Frech and 
on no occasion has the description agreed closely with his.’ In fact Frech’s drawing 
(pl. 1, fig. 3a) more accurately portrayed the dissepimental structure of D. minus 
(except for the divergence of the septal trabeculae) than either Fliigel’s (1956), 
text-fig. Ic) or Schouppé’s (1958, text-figs. 13, 14) illustrations. 

Dr. W. A. Oliver Jr. has kindly sent the writer two small fragments (BM(NH) 
R463661/—2) from a large colony of Acinophyllum simcoense from the Bois Blanc 
Formation (south quarry, Haldimand Quarries and Construction Ltd., north east 
of Hagarsville, Ontario). Slides cut from this material show well developed peneckiel- 
loid dissepiments in longitudinal-section extremely similar to those of P. minor. 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 273 


Where subsidiary dissepiments are developed, however, these are normal globose 
vesicles; no horseshoe dissepiments have been seen. The septal carination in 
cross-section is very variable and smooth septa do occur. Certainly the presence or 
absence of carinae cannot be considered to be of great significance here at the generic 
level. On all other characters, the specimen of A. simcoense can be placed with 
little doubt in Peneckiella and Acinophyllum is thus considered a junior synonym 
of that genus. 

R6dzkowska (1960 : 35) erected a new genus and species, Sudetia lateseptata which 
she considered (1960 : 50) to be a direct phylogenetic descendant of, and closely 
related to Peneckiella. The author is of the same opinion but believes that Sudetia 
does not warrant separate generic status. 

Peneckiella, as suggested by Rdzkowska (1960), apparently evolved from Thamno- 
phyllum, chiefly by the fusion and modification of the horseshoe and flat dissepiments 
characteristic of the latter, leading to the diversification of dissepimental types found 
in Peneckiella. Besides the characteristic peneckielloid dissepiments, forms such as 
P. minor kunthi (Dames) (see Rozkowska 1960, text-fig. 27), P. mesa (Hill) (see 
Strusz 1965, text-fig. 156) and P. salternensis sp. nov. (see p. 274), include varying 
proportions of horseshoe, flat and sigmoidal dissepiments in their dissepimentaria. 
In fact, a morphological series can apparently be traced from a horseshoe and flat 
dissepimental pair, through sigmoidal to peneckielloid dissepiments. P. minor 
sensu stricto, with a fairly uniform peneckielloid dissepimentarium and only rare 
horseshoe dissepiments would appear to be an advanced form and P. lateseptata, 
as suggested by Rozkowska, a late stage form in this evolutionary trend. 


Peneckiella salternensis sp. nov. 
Plate 18, figs. 1-4 
1965 Peneckiella cf. minor (Roemer); Scrutton: 188, text-fig. 1. 
DERIVATION OF NAME. After the type locality in Saltern Cove. 


Diacnosis. Phaceloid Peneckiella. Mean tabularium diameter 3:51 mm., mean 
corallite diameter 5-28 mm. with 17 to 21 major septa (topotype sample). Septa 
slightly and variably dilated; may be weakly carinate. Dissepimentarium domi- 
nated by peneckielloid dissepiments, but with horseshoe, flat and sigmoidal dissepi- 
ments also present. Tabulae regularly developed in form of wide, flat-topped domes. 
Increase lateral. 


HoLotyPeE. OUM D548. Frasnian; thick bedded limestone immediately above 
igneous rock; southern end of Saltern Cove (SX 89505842), near Paignton, south 
Devon. 


MATERIAL. Saltern Cove (main Peneckiella horizon); measured material: OUM 
D501, OUM D546-48, OUM D550-51, OUM D553; additional material: OUM 
D549, OUM D552. Saltern Cove (thin bedded limestones): OUM D554. 

DISTRIBUTION. Frasnian; type horizon (main Peneckiella horizon) and from 
thin bedded limestones in the sequence immediately above, southern end of Saltern 
Cove, south Devon. 


274 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


DESCRIPTION. Colonies are phaceloid with circular to sub-circular, close spaced 
corallites. External features are unknown as the specimens are preserved in a 
tough matrix. The epitheca is o-I mm. or slightly less in thickness. 

The major and minor septa are variably dilated in the dissepimentarium, occasion- 
ally strongly spindle-shaped but showing all gradations to a virtually unthickened 
state. Their thickness ranges from about 0-3 mm. to 0-I mm. or slightly less. The 
septa may be straight or zigzagged in this zone, and are sometimes variably carinate. 
Carinae are yardarm on straight septa and xyloid on zigzagged septa. 

Minor septa end at the tabularium junction but the major septa, slightly attenuated, 
continue into the tabularium with a thickness of about 0-05 mm. or less. The major 
septa may be straight to slightly sinuous in the tabularium and normally extend 
about half way to the axis. Septal length is somewhat variable, however, and 
rarely they may more or less reach the axis or, conversely, only just penetrate into 
the tabularium. The axial ends of the major septa may rarely be slightly thickened. 

The traces of one or two rows of dissepiments, uniserial between adjacent septa, 
may be seen in cross-section. The tabularium junction can be easily distinguished 
but it is not usually strongly defined. 

In longitudinal-section, the dissepimentarium is composed of one or two series of 
highly variable dissepiments. The peneckielloid form dominates when the dissepi- 
mentarium is usually but not always uniserial. The occurrence of horseshoe dissepi- 
ments may be accompanied by peripheral flat dissepiments but normally the latter 
are very rare; horseshoes always occur in the inner row of biserial parts of the 
dissepimentarium. Sigmoidal dissepiments occur with about the same frequency as 
horseshoe dissepiments. The ratio of peneckielloid dissepiments to horseshoe 
dissepiments is highly variable from corallite to corallite, ranging between extremes 
of 2:1 and10:1. The various dissepimental types are randomly distributed up 
the length of the corallites and the vertical spacing of the dissepiments may vary 
from o-I to 0-5 mm. 

Tabularium structure is very constant, consisting of regularly and closely spaced, 
wide, flat-topped domes. Periaxial tabulae in the form of steeply dipping peripheral 
vesicles may sometimes occur. There are about 40 tabulae in I cm. 

Increase is lateral corresponding closely to the ‘ thamnophylloid lateral’ type 
described by R6zkowska (1960 : 31). The diameters of parent corallites displaying 
increase range from 5:3 to 5-6 mm. 

A statistical analysis of the Saltern Cove material has been made but unfortunately 
individual colonies could not be distinguished. The statistics are listed in Table 15¢ 
and illustrated graphically in Text-fig. 210. 

Discussion. Peneckiella salternensis can be distinguished from P. lateseptata 
(Rdzkowska), P. nalivkint Soshkina and P. achanatensis Soshkina on dissepimental 
character alone. The latter three are all characterized by almost exclusively 
uniserial dissepimentaria of uniformly developed peneckielloid dissepiments. P. 
minor minor (Roemer) apparently has a somewhat less regular dissepimentarium, 
with the presence of occasional horseshoes. The tabularium, however, although 
sometimes developing dome-shaped plates, shows tabulae irregularly developed and 
frequently depressed in the axial area. This is in strong contrast to the regularly 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 275 


developed dome-shaped tabulae characteristic of P. salternensis. In addition, data 
given by Fliigel (19560 : 359) for P. minor minor (Table 16) shows that subspecies 
to be smaller, with fewer septa than P. salternensis. 

P. minor kunthi (Dames), P. mesa (Hill) and P. boreensis Strusz have dissepimentaria 
of similar complexity to P. salternensis. P. minor kunth, however, has flat, or more 
commonly, incomplete, axially depressed tabulae and is smaller (Table 16) than P. 
salternensis. P. mesa and P. boreensis have flat-topped domes in their tabularia, 
but both Australian species have axial increase in contrast to the lateral increase in 
P. salternensis. In addition, P. salternensis is larger than P. mesa and P. boreensis 
(see Table 16) and the latter is further distinguished by excessive dilatation of the 
septa in the dissepimentarium. 


TABLE 16.—Quantitative comparison of some species and subspecies of Peneckiella. 


d dt n 
P. salternensis O.R. 4°0-6°3 2°7-4°3 17-21 
Paignton, S. Devon, X 5°28 3°51 I9‘QI 
England. 
P. minor minor O.R. 3°5-4°9 2°9-3°9 15-18 
Harz, Germany. tT. &X 3°9 
P. minor minor O.R. 3°5-5°6 2°9-4°2 14-18 
Antitaurus, Turkey. I xX 4:8 
P. minor kunthi O.R. 2:5-4:8 12-18 
Mokrzeszéw, Poland. 2 xX 
P. mesa O.R. I*4-8-4 I*0-3°9 II-23 
Wellington, N.S.W., x 3:6 BORD 17-00 
Australia. 3 
P. boreensis O.R. O'Q-I0'I 0°7-6:°5 3-28 
Molong, N.S.W., xX 4°5 2:8 16-00 
Australia. 3 


Data from 1 Fliigel, 1956b: 359. 
2 Rézkowska, 1960: 29. 
3 Strusz, 1965: 557, 562. 


Unfortunately data given for other species and subspecies of Peneckiella are not 
in a form allowing statistical comparison with the present material. Nevertheless 
they afford a valuable general indication of quantitative relationships and are there- 
fore listed in Table 16. 


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280 COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 


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ADDENDUM 


Whilst this paper was in press, J. E. Sorauf, (1967, Paleont. Contr. Umiv. Kans., 
16 : 1-41) published a work describing phillipsastraeids from the Frasnian of Belgium. 
The opportunity is taken here to comment briefly on some of the more important 
points discussed by Sorauf which bear closely on the present paper. 

Sorauf (pp. 5, 15) introduces the term “ pseudocerioid ’’, which he defines and 
uses in precisely the same way as in the present paper. It is gratifying to note that 
independent work by Sorauf and the writer on the same species (principally Frechas- 
traea goldfusst and F. pentagona) has led to the same interpretation of the corallite 
wall structure. Sorauf (p. 5), however, infers that species of Piillipsastrea and the 
Phillipsastraeidae are never cerioid whereas the genus and family as defined here do 
include massive forms with an epitheca between at least some of the corallites 
(this paper, p. 210). 

Sorauf (p. 13) separates Phillipsastrea and Pachyphyllum by restricting the latter 
genus to species with a perfect single series of horseshoe dissepiments. In Phillipsas- 
trea he includes a complete range of dissepimental form, from specimens lacking any 
sign of horseshoe dissepiments to those in which an almost complete series is present. 
In fact this whole range is represented in Sorauf’s concept of a single species of 
Phillipsastrea, P. hennahi (fig. 5, Ic and 2). 


COLONIAL PHILLIPSASTRAEIDAE FROM S.E. DEVON 281 


Apart from the difference in the degree of development of the horseshoe dissepi- 
ments, species of Phillipsastvea and Pachyphyllum show no significant divergence in 
their basic morphology to warrant generic separation. Moreover, when the develop- 
ment of horseshoe dissepiments is closely examined even this criterion is, in the 
writer’s opinion, impossible to maintain (compare the longitudinal-section of a 
topotype of Pachyphyllum bouchardi (Semenoff-Tian-Chansky 1961, pl. 9, fig. 2) with 
a section attributed by Sorauf (fig. 5, 2) to Phillipsastrea hennaht). 

The writer is also unable to agree with Sorauf’s (p. 26) interpretation of Phillipsas- 
trea hennaht. None of the illustrations (figs. 5, 1a—c; 8, 1a—d: figs. 5, Id-e; 5, 2 
are longitudinal-sections only) is considered consubspecific with Phillipsastrea 
hennahi hennahi herein, whilst two specimens (figs. 5, 2; 8, 1a—b) are possibly con- 
subspecific with P. hennahi usshert subsp. nov. The significance of this should not 
be overlooked. P. hennahi hennali appears to be characteristic of the middle 
and upper Givetian of England (this paper, p. 216), not of the Frasnian as stated 
by Sorauf (pp. 23, 27). On the other hand, the subspecies P. hennahi ussheri is found 
in the English Lower Frasnian. 

The same English Lower Frasnian limestones yield Frechastraea pentagona pentagona 
and F. pentagona minima. Both subspecies were considered, the latter by inference, 
to be upper Frasnian index forms by Sorauf (pp. 31, 33). 


GEOL. 15, 5 27 


PA AGE 
Phillipsastrea hennahi hennahi (Lonsdale) 


Fic. 1. Cross-section (slide). GSM PF1245 (cut from lectotype). 3. 

Fics. 2,3. Longitudinal-sections (slide). GSM PF1249 (cut from lectotype). 4. 

Fic. 4. Longitudinal-section (peel). GSM PF4028 (taken from lectotype). 4. 

Figs. 1-4 all upper Givetian, Barton Quarry. 

Fic. 5. Longitudinal-section (peel). TM(JB) 79; upper Givetian, Lummaton Quarry. 
x4. 

Fic. 6. Longitudinal-section (peel). GSM PF4028 (taken from lectotype); upper Givetian, 
Barton Quarry. 4. 


PLATE 1 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 5 


28 


GEOL. 15, 5 


PLATE 2 
Phillipsastrea hennahi hennahi (Lonsdale) 


Fic. 1. Cross-section (peel). TM(JB) 79; upper Givetian, Lummaton Quarry. x3. 

Fic. 2, 3. Cross- and longitudinal-sections (peels). O0UM D74/pr (from holotype of Astraea 
iniercellulosa Phillips); ?Middle Devonian, Torquay. x2. 

Fic. 4. Cross-section (peel). GSM PF4029 (from lectotype of Syvingophyllum cantabricum 
Edwards & Haime); ?Middle Devonian, Torquay. x2. 


Bull. Br. Mus. nat. Hist. (Geol.) 


GEOL. 15, 5 


5 


28§ 


PLATE 3 
Phillipsastrea hennahi ussheri subsp. nov. 


Fic. 1. Cross-section (slide). OUM D544/p1. x3. 
Fic. 2. Longitudinal-section (slide). OUM D544/p2. x5. 
Both cut from holotype; Lower Frasnian, road cutting 20 yd. west of Ramsleigh Quarry 
entrance. 
Fic. 3. Cross-section (peel). BM(NH) R5616; Lower Frasnian, Ramsleigh Quarry. 
x3: 


PATE 3 


Bull. By. Mus. nat. Hist. (Geol.) 15, 5 


ITE: 


x2 


Fic. 
FIG. 
Fic. 


Ww 


PLATE4 
Phillipsastrea devoniensis (Edwards & Haime) 


Cross-section (peel). OUM D277/p1; ?Middle Devonian, Rocky Valley, Torquay. 


Cross-section (slide). BM(NH) R29996; Middle Devonian, Torquay. Xz. 
Longitudinal-section (peel). 3. 
Cross-section (peel). x2. 


Figs. 3 and 4 both TM(JB) 105; (?) upper Givetian, Lummaton Quarry. 


Bull. By. Mus. nat. Hist. (Geol.) 15, 5 PLATE 4 


STAY Ms 
Rey, 


Fic. 
Fic. 
Fic. 
Fic. 


AON 


PLATE 5 
Phillipsastrea ananas (Goldfuss) 


Longitudinal-section Sk BM(NH) R46158c. x4. 
Cross-section (slide). M(NH) R46158a. x2. 
Cross-section (slide). M(NH) R46159a. x2. 
Longitudinal-section ee BM(NH) R46159b. x4. 


All omes Frasnian, road cutting south side 30-35 yds. west of Ramsleigh Quarry entrance. 


5 


PEALE 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 5 


+ 


PLATE 6 
Phillipsastrea rozkowskae sp. nov. 


Fic. 1. Cross-section (slide). BM(NH) R46156a (cut from holotype). 2:5. 
Fics. 2, 3. Longitudinal-sections (slide). BM(NH) R46156bd (cut from holotype). 5. 
Fic. 4. Cross-sections (slide). BM(NH) R46157a. 2:5. 

All Lower Frasnian, road cutting south side 25 yds. west of Ramsleigh Quarry entrance. 


Frechastraea pentagona pentagona (Goldfuss) 


Fic. 5. Cross-section (slide). OUM D537/p1; Lower Frasnian, road cutting 20 yds. west 
of Ramsleigh Quarry entrance. X4. 


PLATE 6 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 5 


ie 


pst 


G 


of 


hae 
wo" 


PLATE 7 


Frechastraea pentagona pentagona (Goldfuss) 
Cross-section (slide) OUM D537/p1; Lower Frasnian, road cutting 20 yds 
west of Ramsleigh Quarry entrance. 


x8. 
Fic. 2. Cross-section (peel). 
FIGS. 3, 4. 


PIG. I. 


OUM D279/p1; Lower Frasnian, Ramsleigh Quarry. x6. 
Longitudinal-sections (slide). 


OUM D537/p2; Lower Frasnian, road cutting 
20 yds. west of Ramsleigh Quarry entrance. x8. 
Fic. 5. Longitudinal-section (slide). 


Geol.-Pal. Inst. Bonn, Goldfuss Colln. 206 (cut from 
lectotype); Frasnian, Namur, Belgium. x8. 


if 


PLATE 


(Geol.) 15, 5 


nat. Hist. 


Mus. 


Bull. Br. 


- 


BOS a ee tog 


&%,; i. . <O® Us 

Carr! or 28 Fe Ce Ee Ha) 2ST ae 
Ro hae Pty Bees ha 
1p RAD tae Ch Sire 


nek haw Siry~ be 
“F: He 4 
SW Bs 
<t % 


<9 , ® 
‘HOR 
-* 


ORS PaBIgh 
2 


> 


PLATE 8 
Frechastraea pentagona (Goldfuss) minima (Rézkowska) 


Fic. 1. Cross-section (peel). GSM PF4031 (taken from GSM 73118); Lower Frasnian, 
Ramsleigh Quarry. X4. 

Fics. 2, 3. Longitudinal-sections (slide). GSM PF4032 (cut from GSM 73118); Lower 
Frasnian, Ramsleigh Quarry. x8. 


Frechastraea micrommata (C. F. Roemer) 


Figs. 4, 5. Cross- and longitudinal-sections (slides). Geol.-Pal. Inst. Bonn 34 (cut from 
lectotype); Frasnian, Ferques near Boulogne, France. X4. 


PLATE 8 


Bull. By. Mus. nat. Hist. (Geol.) 


e. ee, 


a 


ns 


” 


yy 


+ bs 


BBS vy 3 
ODD in 


PLATE 9 
Frechastraea carinata sp. nov. 


Fic. 1. Cross-section (slide). OUM D3090 (cut from holotype); Lower Frasnian, road 
cutting 80 yds. west of Ramsleigh Quarry entrance. x6. 

Fic. 2. Cross-section (peel). BM(NH) R5634; Lower Frasnian, Ramsleigh Quarry. x6. 

Fic. 3. Longitudinal-section (slide). 0UM D300d (cut from holotype); Lower Frasnian, 
road cutting 80 yds. west of Ramsleigh Quarry entrance. x6. 


PLATE 9 


Mus. nat. Hist. (Geol.) 15, 5 


Bull. Br. 


as 


igs 


7 


By 


F ie Pep . 


i Sap 
eS F58 


“ae Th 


ra 24 M 
Ww y 
yf my * 
8 4 
¢ FY 
rer C Ug 
. 
‘ 3 . ; 
‘ 5 
i 
‘ 2 4 ta 
ae s Pay Yates 


pee 


BS 


PLATE 10 
Frechastraea goldfussi (de Verneuil & Haime) 


Fic. 1. Cross-section (slide). OUM D540/pz. 5. 
Fics. 2, 3. Cross-sections (slide). OUM D539/p2.  X5. 
Fic. 4. Longitudinal-section (slide). OUM D541/pz. x6. 
Fic. 5. Longitudinal-section (slide). OUM D540/p1. x8. 
All Lower Frasnian, Ramsleigh Quarry. 


Jed ‘5 
tet. | 
SS. (7 
By he) ay, re 
ia Hy 


EG aele 
FIG. 2. 


RIE, 3, 


PLATE 11 
Frechastraea goldfussi (de Verneuil & Haime) 


Longitudinal-section (slide). OUM D540/pr. x8. 
Cross-section (peel). TM(JB) 318. x7. 
Figs. 1 and 2 both Lower Frasnian, Ramsleigh Quarry. 


Frechastraea bowerbanki (Edwards & Haime) 


Cross-section (peel). TIM 136/7; Lower Frasnian, Ramsleigh Quarry. 


x10. 


PReAWE n1 


re a 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 5 


a 


Bh 


= 


> 
a? 

rey 4 

. ae? 


Nes 


\ 


¥ 


\ 
% 
¥ 


a 


29 


GEOL. 15, 5 


PLATE 12 
Frechastraea bowerbanki (Edwards & Haime) 


Fic. 1. Cross-section (peel). TM 136/7. 3. 
Fic. 2. Longitudinal-section (slide). BM(NH) R46373. x6. 
Fic. 3. Longitudinal-section (slide). TM 136/7. x6. 

All Lower Frasnian, Ramsleigh Quarry. 


PEALE 12 


Bull. By. Mus. nat. Hist. (Geol.) 15, 5 


Wey 


Paar ittaye 
Pony 


there tt ert 


. 
": 
Far oainpe yD 


ne We 
Papa tenp sma ore mele BSD 
{48 BaRMAEOD TAT HEE Oyen ee 
SL ietalet troy ty tuned 
ES alle tastier 


+ RhOTP oestagsy rein Dearne 


PLATDE 13 
Thamnophyllum germanicum schouppei nom. nov. 


Fic. 1. Cross-section (slide). OUM D509/p1; lower Givetian, Dyer’s Quarry. X50. 
Fic. 2. Cross-section (slide). Pal. Inst. Graz UPG 327 (cut from holotype); Middle 
Devonian, Torquay. X4. 
Fic. 3. Cross-section (peel). OUM D507/3/p1. x4. 
Fic. 4. Cross-section (slide). OUM D509/pt1. x4. 
Figs. 3 and 4 both lower Givetian, Dyer’s Quarry. 


Bull. By. Mus. nat Hist. (Geol.) 15, 5 PAE ors 


ie ~ 


PLATE 14 
Thamnophyllum germanicum schouppei nom. nov. 


Fics. 1, 2. Longitudinal- and cross-sections (slide). OUM D509/p1. 4. 
Fic. 3. Longitudinal-section (peel). OUM D507/2/pi. x4. 
Fic. 4. Longitudinal-section (peel). OUM D508/4/p2. 4. 

All lower Givetian, Dyer’s Quarry. 


PLATE 14 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 5 


PLATE 15 
Thamnophyllum caespitosum paucitabulatum subsp. nov. 


Fic. 1. Cross-section (slide). BM(NH) R46163b; upper Givetian, Lummaton Quarry. 


ie 
Thamnophyllum caespitosum (Goldfuss) sensu lato 


Fic. 2. Longitudinal-section (slide). BM(NH) R46168a. x4. 
Fic. Cross- and longitudinal-sections (slide). BM(NH) R46171a. x4. 
Fic. 4. Cross-section (slide). BM(NH) R46168a. x4. 

Figs. 2-4 all middle Givetian, Wolborough Quarry. 


ee 


PLATE 15 


Bull. By. Mus. nat. Hist. (Geol.) 15, 5 


Fic. 


Fic. 2 


Fia. 
Fic. 
Fic. 
Fic. 
Fie. 


NANA WwW 


PLATE 16 
Thamnophyllum caespitosum (Goldtfuss) sensu lato 


Cross- and longitudinal-sections (slide). BM(NH) R46168a. x1. 
Longitudinal-section (slide). BM(NH) R46175b. x4. 
Both middle Givetian, Wolborough Quarry. 


Thamnophyllum caespitosum paucitabulatum subsp. nov. 


Cross-section (slide). BM(NH) R46163b. x1. 
Cross-section (slide). BM(NH) R46165a (cut from holotype). x1. 
Cross-section (slide). BM(NH) R46165a (cut from holotype). x4. 


Longitudinal-section (slide). BM(NH) R46165c (cut from holotype). 
Longitudinal-section (slide). BM(NH) R461656 (cut from holotype). 


Figs. 3-7 all upper Givetian, Lummaton Quarry. 


x4. 


PLATE 16 


Bull. Br. Mus. nat. Hist. (Geol.) 15. 5 


A ot ote gees, 


fy x 


Ne. 


ee ee 
To. 6 gts, 


a ae 


‘<< iedeas Oe ae S, s np ae 


ow ae 
ge 


ee 


~ 


PLATE 17 
Thamnophyllum caespitosum paucitabulatum subsp. nov. 


Fic. 1. Cross-section (slide). BM(NH) R46165a (cut from holotype). x4. 
Fic. 2. Longitudinal-section (slide). BM(NH) R46163c. x4. 
Fic. 3. Longitudinal-section (slide). BM(NH) R46164d. x4. 

All upper Givetian, Lummaton Quarry. 


Peneckiella minor minor (F. A. Roemer) 


Fic. 4. Cross-section (slide). x3. 
Fic. 5. Longitudinal-section (slide). x6. 
Figs. 4 and 5 both Bergakad. Clausthal-Z. 117 (cut from holotype); Frasnian, Winterburg 
near Bad Grund, Germany. 


PLATE 17 


Bull. By. Mus. nat. Hist. (Geol.) 15, 5 


Fic. 
Fic. 
Fic. 
Fic. 


AWN 


PLATE 18 
Peneckiella salternensis sp. nov. 


Cross-section (slide) OUM D546/pr. x3. 
Cross-section (slide). OUM D548/pr. (cut from holotype). x3. 


Longitudinal-section (slide). OUM D548/p3 (cut from holotype). 


Longitudinal-section (slide). OUM D546/p3. x4. 
All Frasnian, main Peneckiella horizon, Saltern Cove. 


x 4. 


PLATE 18 


Bull. Br. Mus. nat. Hist. (Zool.) 15, 5 


tet 


she 


ae 


= ¥ 
BY ADLARD 


AS bcs ee 


15 May 1966 


Za 


SOME STROPHOMENACEAN 

ak BRACHIOPODS 

FROM THE BRITISH LOWER 
Hi SILURIAN 


gy wos” 


L. R..M. COCKS 


- BULLETIN OF 
JE BRITISH MUSEUM (NATURAL HISTORY) 
EOLOGY on Vol. 15 No. 6 
LONDON: 1968 


Soc oo 
ci AAR AA 
“iy 


SOME STROPHOMENACEAN BRACHIOPOD 
FROM THE BRITISH LOWER SILURIAN 


BY 
LEONARD ROBERT MORRISON COCKS _ / 


De oe 
British Museum (Natural History) 


Pp. 283-324; 14 Plates; 1 Text-figure 


BULLETIN OF 
THE BRITISH MUSEUM (NATURAL HISTORY) 
GEOLOGY Vol. 15 No. 6 


LONDON : 1968 


THE BULLETIN OF THE BRITISH MUSEUM 
(NATURAL HISTORY), iistituted in 1949, 1s 
issued tn five series corresponding to the Departments 
of the Museum, and an Historical series. 

Parts will appear at irregular intervals as they become 
veady. Volumes will contain about three or four 
hundred pages, and will not necessarily be completed 
within one calendar year. 

In 1965 a separate supplementary series of longer 
papers was instituted, numbered serially for each 
Department. 

This paper ts Vol. 15, No. 6 of the Geological (Palae- 
ontological) sertes. The abbreviated titles of periodicals 
cited follow those of the W orld List of Scientific Periodicals. 


World List abbreviation : 
Bull. Br. Mus. nat. Hist. (Geol.). 


© Trustees of the British Museum (Natural History) 1968 


LRUSE Ee Bs Or 
THE BRITISH MUSEUM (NATURAL HISTORY) 


Issued 14 May 1968 Price £2) 0s 


SOME STROPHOMENACEAN BRACHIOPODS 
FROM THE BRIEISH LOWER SILURIAN 


Biri ie ME COCKS 


CONTENTS 


I. INTRODUCTION ; é c C , : : ; ; 286 
II. SYSTEMATIC DESCRIPTIONS . : é é é : F 6 286 
Superfamily Strophomenacea King . ! : : : . 286 
Family Strophomenidae King : : 5 : ‘ ; 288 
Subfamily Strophomeninae King ‘ - : : ‘ 289 
Genus Pentlandina Bancroft . j : : ; : 289 
Pentlandina tavtana Bancroft . 2 ; . : 289 
Pentlandina parva Bancroft . ; : ‘ : 291 
Pentlandina parabola sp. nov. . é ; : : 292 
Pentlandina sp. . i é ; 5 : 293 

Subfamily Furcitellinae W Akers : : : ; 293 
Genus Katastrophomena nov. : ; : ; 293 
Katastrophomena woodlandensis (Reed) : : : 295 
Katastvophomena scotica (Bancroft) . ‘ : : 296 
Katastrophomena penkillensis (Reed) , ; ; 207 
Katastrophomena sp. 9 : 3 : : 298 

Subfamily Leptaeninae Hall & Clarke : 2 3 ; 299 
Genus Leptaena Dalman : : : 3 ; : 299 
Leptaena martinensis sp. nov. . : c : . 302 

Leptaena haverfordensis Bancroft. : : ; 304 

Leptaena valida Bancroft : ; : : F 305 

Leptaena urbana Bancroft : P : : : 305 

Leptaena conteymina sp. nov. . : j : : 306 

Leptaena valentia sp. nov. : : : : 307 

Leptaena valentia mullochensis Snes, nov. ; ; 309 

Leptaena zeta Lamont . : : ¢ : ; 309 
Leptaena rveedi sp. nov. . ; ‘ : : ; 310 

Leptaena ziegleri sp. nov. : : : : : 311 

Leptaena quadvata Bancroft . ; : : : B12 

Leptaena purpurea sp.nov. . : : : > 313 

Leptaena sp. ‘ : : : ; : 314 

Genus Cyphomena @oones : ; : : . : 315 
Subgenus Cyphomenoidea nov. . F 316 

C. (Cyphomenoidea) wisgoriensis (L sso & Gilbert) : 316 

Subgenus Laevicyphomena nov. . : . 2 317 

C. (Laevicyphomena) feliciter sp. nov. : , : 317 

Genus Mackerrovia gen. nov. ‘ F : 319 
Mackerrovia lobatus (Lamont & Gilbert) ; : : 319 

Genus Bellimurina Cooper. : : : : , 321 
Bellimurina sp. . : : : : : : 321 

Il]. AckKNOWLEDGMENTS : : ‘ : ‘ : : : 322 
IV. REFERENCES . j : : F : : F 322 


GEOL. 15, 6. 30 


280 BRITISH LOWER SILURIAN 


SYNOPSIS 


The brachiopod family Leptaenidae is relegated to subfamilial rank within the Strophomenidae. 
All the known British Lower Silurian (Llandovery) species from the revised family Stropho- 
menidae are described and figured. Two new genera are erected: Katastvophomena, type 
species Stvophomena antiquata var. woodlandensis Reed 1917, and Mackeryovia, type species 
Brachyprion avenaceus var. lobatus Lamont & Gilbert 1945. Two new subgenera are erected 
within the genus Cyphomena Cooper 1956 (hitherto thought to be confined to the Ordovician) : 
Cyphomenoidea, type species Leptaena wisgoriensis Lamont & Gilbert 1945, and Laevicyphomena, 
type species C. (L.) felicitey sp. nov. Eight new species and one subspecies are erected, and 
the ecological communities of all the species recorded. 


i, INTRODUCTION 
THREE families of the superfamily Strophomenacea occur in the British Lower 
Silurian. One, the Stropheodontidae, has already been considered (Cocks 1967), 
and thus the present paper is concerned exclusively with representatives of the 
other two families, the Strophomenidae and the Leptaenidae. 

Strophomenids are widely distributed in the Lower Silurian of Britain, but are 
sporadic and rare at most localities. They have been recorded under the name 
‘ Strophomena antiquata’ in most faunal lists. Leptaenids are rather commoner and 
have usually been referred to ‘ Leptaena rhomboidalis’. Although the Wenlock 
species of both families have been figured for many years, notably by Thomas 
Davidson in various works, the Llandovery species have remained for the most 
part poorly described. 

The stratigraphy and correlation of the British Llandovery is at the present 
time under review, and a joint paper by Dr. A. M. Ziegler, Dr. W. S. McKerrow 
and the present author is in course of preparation. Correlation between the various 
areas and the type area of Llandovery itself has been effected mainly by the use of 
evolving brachiopod lineages such as those of Stvicklandia (Williams 1951) and 
Eocoelia (Ziegler 1966). 

it, SYSTEMATEC DP SERIP TIONS 
Superfamily STROPHOMENACEA King, 1846 
Classification 


In the recent Treatise (Williams et al. 1965), the classification of the Stropho- 
menacea is as follows: 


Superfamily Strophomenacea King 1846 (L.Ord.-L.Carb.) 
Family Strophomenidae King 1846 (L.Ord.-L. Dev.) 
Subfamily Strophomeninae King 1846 (M.Ord.-U.Sil.) 

Furcitellinae Williams 1965 (M.Ord.-L.Sil.) 
Rafinesquininae Schuchert 1893 (M.-U.Ord.) 
Glyptomeninae Williams 1965 (L.-M.Ord.) 
Oepikinae Sokolskaya 1960 (M.-U.Ord.) 
Leptaenoideinae Williams 1953 (U.Sil.-L.Dev.) 

Family Foliomenidae Williams 1965 (U.Ord.) 

Family Christianiidae Williams 1953 (Ord.) 

Family Leptaenidae Hall & Clarke 1894 (M.Ord.-L.Carb.) 

Family Stropheodontidae Caster 1939 (U.Ord.-U.Dev.) 


STROPHOMENACEAN BRACHIOPODS 287 


The Stropheodontidae is divided into seven subfamilies which are outside the 
scope of the present paper; the family is distinct in possessing denticles, and was 
held with some justification to possess superfamilial status by Sokolskaya (1960 : 
213). Of the remaining families, the Foliomenidae and the Christianiidae are 
confined to the Ordovician, leaving the Strophomenidae and Leptaenidae to be 
considered here. 

There is some doubt as to whether these two families are validly separable. Apart 
from the undiscussed list at the end of Hall & Clarke (1894 : 353-354), which divided 
what are now known as the suborders Strophomenidina and Triplesiidina into a 
rather arbitrary division between Strophomenidinae and Leptaenidae (thus creating 
the latter family), the two families were not divided again until 1956 in Cooper’s 
great work on the Chazyan brachiopods. Thus Williams in his paper on stropho- 
menoid classification (1953) did not mention the Leptaenidae: he divided the 
Strophomenacea into three families, the Strophomenidae, Stropheodontidae and 
Christianiidae, and the Strophomenidae was divided into only two subfamilies, 
the Strophomeninae and the Leptaenoideinae. In fact he specifically cited the 
Rafinesquinidae and Strophomenidae as synonymous (1953 : 8). 

Cooper (1956) divided the Chazyan Strophomenacea into three families, Leptaen- 
idae, Christianiidae and Strophomenidae. He briefly defined the three families as 
follows—Leptaenidae: “Compressed to faintly lenticular Strophomenacea with 
large apical foramen’ (1956 : 820); Christianiidae: ‘Smooth or finely costellate 
Strophomenacea having 4 prominent septa in the brachial valve’ (1956 : 859); 
and Strophomenidae: ‘ Strophomenacea having either normal or reversed convexity 
of the valves and a small foramen in the pedicle valve’ (1956 : 866). Thus, by 
those definitions, the only difference between a leptaenid and a strophomenid of 
normal convexity lies in the size of the foramen. As many species of Leptaena 
itself, e.g. L. salopiensis Williams, possess a foramen which is ‘ small, commonly 
sealed in adult shells’ (Williams 1963 : 461), this definition cannot be used in the 
type genus of the family. Even the geniculation and disc rugae may be seen on 
some genera, for example Luaia RoOmusoks 1956, ascribed to the Strophomeninae 
by Williams (1965 : H384). 

However, there does occur a group of strophomenaceans which are normally 
geniculate and often possess rugae over most of the disc, and which may conveniently 
be grouped with Leptaena itself. But, bearing in mind the wide differences between 
the Strophomenidae, Christianiidae and Stropheodontidae, familial recognition as 
the Leptaenidae seems an unwarrantedly high taxonomic rank. In this paper 
they will be treated as a subfamily within the Strophomenidae, the Leptaeninae, 
although even this separation may not be valid, and some of the subfamilies may 
be inter-phyletic. 

Although only three are considered in this paper, this arrangement leaves a total 
of seven subfamilies within the Strophomenidae, and their relative phylogenies 
leave much scope for discussion. Certainly the morphology of the two genera in 
the Leptaenoideinae, Leptaenoidea and Leptaenisca, seem to indicate descent from 
leptaenids rather than from other strophomenids, and this is supported by their 
known stratigraphical range. 


288 BRITISH LOWER SILURIAN 


Ecological occurrence 


The species described in this paper are distributed as follows in the animal com- 
munities established in the British Llandovery (Ziegler 1965, Cocks 19674, Ziegler, 
Cocks & Bambach 1968). The list omits Leptaena urbana Bancroft, whose 
community is unknown. No strophomenids have yet been found in the Lingula 
community, which is thought to have been the shallowest. 


Eocoelia Pentamerus Stricklandia  Clorinda 
Community Community Community Community 

Pentlandina tartana Bancroft : ; —= —- , x 
Pentlandina parva Bancroft ‘ 5 —- ~- x 
Pentlandina parabola sp. nov. b ; —- — — 
Katastvophomena woodlandensis (Reed) . — —- 
Katastvophomena scotica (Bancroft) : _- —- x — 
Katastvophomena penkillensis (Reed). ~ —- 
Leptaena martinensis sp. nov. : : —- -— — 
Leptaena haverfordensis Bancroft . ’ --- — 
Leptaena valida Bancroft. ; : - -- ‘ — 
Leptaena contermina sp. nov. ; : x » — 
Leptaena valentia sp. nov. . : : = z x = 
Leptaena zeta Lamont : F 5 — —- — 
Leptaena reedi sp. nov. 3 : 3 - —- . —- 
Leptaena ziegleyri sp.nov. . : : —- -— : — 
Leptaena quadvata Bancroft : ; = -- -— x 
Leptaena purpurea sp. nov. . c : = — —- 
C. (Cyphomenoidea) wisgoriensis 

(Lamont & Gilbert) : : ; -- y x ? 
C. (Laevicyphomena) felicitey sp.nov. . — — ™ — 
Mackerrovia lobatus (Lamont & Gilbert) — - : — 


Family STROPHOMENIDAE King, 1846 


Apart from the Leptaeninae, there are only two groups of Strophomenidae which 
have so far been found in rocks of Llandovery age, as recognized by Williams (1951 : 
115), who at that time referred them provisionally to Strophomena Rafinesque and 
Holtedahlina Foerste. 

The two groups are here referred to Katastrophomena gen. nov. and Pentlandina 
Bancroft 1949. These are placed in different subfamilies, the Furcitellinae and the 
Strophomeninae, and are the only post-Ordovician genera known in either sub- 
family. The chief subfamilial difference (Williams 1965 : H384, H386) is that the 
Strophomeninae are unequally parvicostellate and the Furcitellinae are costellate, 
but in fact later species of Katastrophomena (such as K. penkillensis (Reed) described 
below) become unequally parvicostellate. Thus in the two genera concerned, the 
chief differences in Silurian species lie in the internal structures of the brachial valve, 
and the usual presence of a strong fold and sulcus in Pentlandina, 


STROPHOMENACEAN BRACHIOPODS 289 


Subfamily STROPHOMENINAE King, 1846 
Genus PENTLANDINA Bancroft, 1949 


1949. Strophomena (Pentlandina) Bancroft : 11, 13. 
1965. Pentlandina Bancroft Williams : H384. 
1966. Pentlandina Bancroft; Boucot et al. : 25. 


DiAGNosIs: Biconvex to convexo-concave small stophomeninids with prominent 
fold and sulcus, often with an ornament of parvicostellae interrupting broken rugae. 


TYPE SPECIES (by original designation); Stvophomena (Pentlandina) tartana Ban- 
croft 1949 from the Upper Llandovery of Deerhope Burn, Pentland Hills, Scotland. 


Species assigned : 

Strophomena (Pentlandina) tartana Bancroft 1949 : 13. Upper Llandovery, Pent- 
land Hills, Scotland. 

Strophomena (Pentlandina) parva Bancroft 1949 : 13, pl. 1, fig. 9. Upper Llan- 
dovery, The Frolic, Haverfordwest, Pembrokeshire. 

Pentlandina parabola sp. nov. Upper Llandovery, Purple Shale, Shropshire. 

Strophomena /urundo Barrande 1879, pl. 47, figs. I-32 pars. Wenlock, Bohemia, 
Czechoslovakia. 

Leptaena loveni de Verneuil 1848 : 339, pl. 4, fig. 5. Visby Marl (Upper Llan- 
dovery) Gotland, Sweden. 

Leptaena parvula Kindle 1915 : 14, pl. I, figs. 5-9. Stonewall Limestone, Sas- 
katchewan, Canada. 

Leptaena sinuosus Kindle 1915: 13, pl. I, figs. 1-4. Stonewall Limestone, 
Saskatchewan, Canada. 

?Leptaena lewist1 Davidson 1847 : 59, pl. 12, figs. 22-24, Lower Wenlock, Rushall 
Canal, Staffordshire. 


Discussion. Pentlandina was raised to generic level by Williams (1965) and 
placed within the Strophomeninae. Boucot et al. (1966) recently removed the genus 
to the Leptaenidae on account of the pedicle muscle field and brachial processes 
and adductor plates (= trans-muscle septa?). It is, however, quite impossible to 
agree with this point, as each of the cited structures in Pentlandina is firmly 
attributable to the Strophomeninae rather than to the Leptaeninae. In fact the 
morphology of Pentlandina tartana, the type species described below, is not like any 
member of the leptaeninids. Taken with a shape so typical of the subfamily, there 
can be no doubt that the genus lies within the Strophomeninae. Gumnnarella 
Spjeldnaes 1957 has a similar ornament to Pentlandina, but is geniculate as opposed 
to biconvex and sulcate. 


Pentlandina tartana Bancroft 
(Pl. 1, figs. 1-6) 


1868. Stvophomena antiquata (J. de C. Sowerby); Davidson : 17, pl. 2, figs. 21-23. 
1871. Strophomena antiquata (J. de C. Sowerby); Davidson : 299 pars, pl. 44, figs. 7-9 only. 
1949. Strophomena (Pentlandina) tartana {Lamont MS) Bancroft : 13, on pl. 1, fig. To. 


290 BRT SIO Were Re Sie Waa AGN 


D1aGnosis: Small strophomeninid with prominent fold and sulcus. Fine orna- 
ment of differentiated parvicostellae which break irregular small weak rugae. 


DeEscrRIPTION. Exterior. Biconvex to slightly resupinate with a semicircular 
outline and small ears. Large sulcus in pedicle valve with corresponding fold in 
brachial valve. Fine ornament of differentiated parvicostellae, and very weak 
irregular rugae of small wavelength distributed over all the shell. Interarea of 
variable size, larger in the pedicle than in the brachial valve. Large delthyrium 
closed at the apex by a small pseudodeltidium (Plate 1, fig. 4). Information un- 
certain as to the chilidium, there is at least a small one developed, but it is not clear 
whether or not part of the delthyrium remained open. 

Pedicle interior. Straight hingeline with prominent teeth connected to the 
posterior end of a strong pair of short muscle bounding ridges which project anteriorly 
as much as dorsally. Short median septum starting close to the apex and dividing 
the muscle bounding ridges before stopping abruptly, leaving an inclined slope about 
2 mm. long at its anterior end, which merges with the valve floor. Diductor scars 
short, leaving concentric growth ridges. Adductor scars elongate, close to, and 
partially on, the median septum. Shell thick posteriorly with prominent pseudo- 
punctae, thin anteriorly, often with an interior reflection of the exterior ornament. 

Brachial interior. Widely divergent prominent socket plates which curve slightly 
posteriorly at their lateral extremities. They are joined medianly to the bilobed 
cardinal process lobes, which are directed ventrally and slightly posteriorly. The 
process lobes are connected to a weak shaft, which in some specimens bifurcates 
anteriorly, in others reunites to form a weak median septum. Trans-muscle septa 
variably developed, but including in all specimens a prominent anterior pair stronger 
than and subparallel with the median septum. These septa are often slightly flared 
ventro-laterally. Owing to the mass of structures in the brachial valve presumably 
mainly used for the support of adductor muscles (although some could have been 
rudimentary brachiophore supports) the scars and shape of the muscles are not 
readily distinguishable. Thick shell with prominent taleolae antero-laterally. 


LECTOTYPE (here selected). BB 31447 (Plate 1, figs. 1, 2), a brachial valve in 
the Davidson collection. One of a number of specimens which made up the material 
for the composite figures cited by Bancroft. With the specimens there is a label 
in Davidson’s handwriting ‘ Strophomena antiquata Sow. bed D. Wenlock Shale, 
Pentland Hills, found by Mr. Henderson.’ The specimens are from an horizon 
now known to be of Upper Llandovery age in the North Esk Inlier of the Pentland 
Hills, Scotland (Mitchell & Mykura 1962 : 12 e¢ seq.). 


DIMENSIONS (in cm.—all specimens from type locality) 


il. Ww. 
BB 31447 Lectotype. Brachial valve . 0-QI approx. 1:6 
B 8485 Brachialvalve . : : 0:92 broken 
BB 31450 Brachial valve. ; : 0-86 1°39 
B 13614 _ ~+Pedicle valve ; , : OV72 129) 


BB 31448 Pedicle valve : 5 : 0°93 approx. I°5 


STROPHOMENACEAN BRACHIOPODS 291 


Discussion. In erecting the species, Bancroft (1949 : 13) quoted those of David- 
son’s figures of Strophomena antiquata which came from the Pentland Hills. He 
also figured a specimen (Plate 1, fig. 10) which is of part of a pedicle internal mould. 
This specimen is not in the Sedgwick Museum and Mr. A. G. Brighton informs me 
(im litt. March, 1967) that its whereabouts are unknown. In many copies of Ban- 
croft’s privately published paper, Dr. A. Lamont has deleted reference to the figure 
in the species description, and substituted ‘S. cf. penkillensis’ as the caption for 
Plate 1, fig. 10, and indeed the specimen is probably of the latter species and may 
be attributed to Katastrophomena of the present paper. Thus, to stabilize the 
identity of Pentlandina, Davidson’s figures have been selected as lectotypes of the 
type species by Havlicek (1968 : 75). The original specimens used by Davidson 
are selected above. 

Apart from the Pentland Hills, the species has not been found in form identical 
with the type. There is, however, a larger form, represented as yet by only one 
pedicle and one brachial valve, probably attributable to P. tavtana, found in one 
locality in the southern Welsh Borderland. This is at Cullimore’s Quarry, Charfield 
Green, Gloucestershire, which lies in Tortworth Beds of C, age, part of the Tortworth 
Inlier. The dimensions are as follows (in cm.). 


Il. Ww. 


BB 31470 Pedicle valve . : approx. 1:3 approx. 2-2 
BB 31471 Brachial valve. : : 1°39 approx. 2-3 


The larger size may well be a phenotypic feature, as there seem to be no differences 
in ornament, internal structures or general proportions between the Tortworth and 
Pentland Hills specimens. 


Pentlandina parva Bancroft 
(Rip wriesa7. 3) 
1949. Strophomena (Pentlandina) parva Bancroft : 13, pl. 1, fig. 9. 
1951. Holtedahlina parva (Bancroft) Williams : 118, pl. 7, figs. 8-10. 

Discussion. A full description of the species is given by Williams (1951), and 
photographs of it are included in the present paper only for completeness and for 
comparison with P. tartana and P. parabola. The species is rare, it has so far been 
recorded only from the type locality, in Uzmaston Beds (Upper Llandovery) of the 
Frolic, south-west of Uzmaston Farm, Haverfordwest, Pembrokeshire. This is the 
same locality (Locality K of O. T. Jones on Sedgwick Museum labels) from which 
comes Leptaena quadrata, dealt with later in this paper, and it is interesting to note 
that neither species has been found except at the type locality. 

To judge from the figures, the species seems to have a close relative in North 
America, the P. cf. parva of Boucot et al. (1966 : 25, pl. 6, figs. 16-18, pl. 7, figs. 
1-10). The American species is, however, twice the size of the Welsh, no mention 
is made of any prominent fold and sulcus, and the arrangement of the brachial 
interior seems closer to P. parabola than to P. parva; all these features give a definite 
impression of specific difference. 


BRITISH LOWER SILURIAN 


1S) 
Ne} 
Ww 


Pentlandina parabola sp. nov. 
(Pl. 1, figs. 9-12) 


Diacnosis. Alate Pentlandina with pronounced fold and sulcus, and two pairs 
of converging muscle ridges in the brachial valve. 


DeEscrIPTION. Exterior. Outline semicircular but laterally alate. A deep ven- 
tral sulcus and dorsal fold are present, but lateral to these, minor frills are some- 
times developed at the valve margin. Ornament of parvicostellae, with fine threads 
between them, more prominently developed in the median plane. New ribs arise 
by intercalation. In addition, small, even concentric rugae, broken by the parvi- 
costellae are present, forming an irregular pattern. Medium-sized interarea, with 
an open delthyrium, bounded laterally by plates (Pl. 1, fig. 10) and a vestigial 
chilidium. Very small supra-apical foramen, atrophied in adult specimens and not 
always on the median plane. 

Pedicle interior. Straight hingeline with prominent teeth which form the posterior 
end of a pair of muscle-bounding ridges of diamond shape, although they only some- 
times meet at their anterior, enclosing a small diductor muscle scar which is weakly 
impressed. No information on the size and shape of the adductor muscle scars. 
Weak, broad median septum not extending anteriorly of the bounding ridges. 
Interior reflection of the ornament usually seen. Thin shell with no prominent 
taleolae showing. 

Brachial interior. Divergent socket plates, curving antero-laterally. Small ven- 
trally directed cardinal process lobes. Scarcely visible platform and weakly im- 
pressed muscle scars, but bounded laterally by two pairs of plates starting posteriorly 
at the lateral ends of the socket plates and set diagonally so that they converge 
anteriorly (but do not meet). Each plate is convex laterally and set at an angle 
to the valve floor. A very weak median septum runs for a short distance anterior 
of the bounding ridges. 


HoLotyPe. OUM Cr13507, a partly exfoliated pedicle valve from the Purple 
Shale (Upper Llandovery) of Domas, Shropshire. Grid Ref. SJ/5936 0062. 


DIMENSIONS (in cm.—all specimens from Domas) 


1. Ww. 
OUM C13507 Holotype Pedicle valve . 0-89 1007/0) 
OUM C13504 Paratype Pedicle valve . 0:68 1322 
OUM C13505 Paratype Brachial valve . broken 2 
OUM C13509 Paratype Brachial valve . 0-26 0-51 


Discussion. Length measurements were made in the median plane, but in old 
individuals there is some shell antero-laterally to this. In the small specimen 
(OUM Cr13509) the fold has not yet started to develop. 

The species is known only from the Purple Shale of Shropshire and is rare, although 
it occurs as 2°% of the population at the type locality. Single specimens are known 


STROPHOMENACEAN BRACHIOPODS 293 


from two other localities, Boathouse Coppice [Grid. Ref. SJ/6205 0398] and Devil’s 
Dingle [Grid Ref. SJ/6392 0547). 

P. parabola differs from P. parva (Pl. 1, figs. 7, 8) in having a still more pronounced 
fold and sulcus, less distinct ornament and in better differentiated alae (without, 
however, being more transverse). In addition the strength, proportion and arrange- 
ment of the brachial internal structures are dissimilar in the two species. From 
P. tartana the new species differs in being more apsacline, more alate, and in having 
a frilly margin, in having a relatively smaller total muscle area and a differently 
shaped socket arrangement and muscle area in the brachial valve. In addition the 
rugae are more prominent, the interior less strongly papillose and the whole shell 
less thick. 


Pentlandina sp. 
(RIs, fieear3)) 


In one block from the Bog Mine, West Shropshire [Grid Ref. SO/3510 9815), 
there is a single broken pedicle valve, BB 31299, which may be referred without 
doubt to Pentlandina, on its general shape, particularly its prominent sulcus, and 
also on the character of the muscle field and bounding ridges. It seems fairly closely 
related to Pentlandina parabola but its shell is rather more irregular; in addition no 
trace of the distinctive ornament may be seen, but this could possibly be due to 
the coarse quartzite matrix. The length is 1-02 cm. and the estimated width 
approximately 1-6 cm. 

The specimen is significant in being the earliest representative of the genus so 
far known, with an age of Middle Llandovery. 


Subfamily FURCITELLINAE Williams, 1965 
Genus KATASTROPHOMENA nov. 


DracGNosis. Resupinate strophomenid with an ornament of irregular subequal 
costellae in early stocks, but may be parvicostellate in later stocks. With dental 
plates and weak trans-muscle septa. 


TYPE SPECIES. Strophomena antiquata var. woodlandensis Reed 1917. 


SPECIES ASSIGNED: 


Strophomena antiquata var. woodlandensis Reed 1917 : 902, pl. 18, figs. 20, 21, 
pl. 19, figs. 1-5. Middle Llandovery, Woodland Point, Girvan, Ayrshire, Scotland. 

Orthis antiquata J. de C. Sowerby in Murchison 1839 : 630, pl. 13, fig. 13. Wen- 
lock Shale, Woolhope, Herefordshire. 

Strophomena dura Bancroft 1949 : 15, pl. 1, fig. rr, Wenlock Limestone. 

Strophonella penkillensis Reed 1917 : 900, pl. 18, figs. rr-13. Upper Llandovery, 
Bargany Pond Burn, Girvan, Ayrshire. 

Orthis scabrosa Davidson 1847 : 61, pl. 13, figs. 14, 15. Wenlock Limestone, 
Benthall Edge, Shropshire. 


294 BRITISH LOWER SILURIAN 


Strophomena scotica {and var. alveata| Bancroft 1949 : 12, pl. I, figs. 4-7, non 
fig. 3. Gasworks Mudstone (Lower Llandovery) Haverfordwest, Pembrokeshire. 

Strophomena woodlandensis geniculata [Bancroft MS nom nud.\ Williams 1951 : 
117, pl. 7, figs. 5-7. Upper Llandovery (C,), Llandovery, Carmarthenshire. 

Strophonella costatula Hall & Clarke 1894 : 359, pl. 84, figs. 15, 16. Niagara 
Group, Louisville, Kentucky, U.S.A. 

Strophomena radiireticulata Twenhofel 1928 : 192, pl. 17, figs. 1-3. Jupiter 
Formation (Upper Llandovery-Wenlock), Anticosti Island, Canada. 

?Strophomena sibirica Andreeva in Nikiforova & Andreeva 1961 : 183, pl. 38, 
figs. I-7. 


Species possibly congeneric : 


Strophomena rugata Lindstrom 1860 : 371, pl. 13, fig. 14. Visby Marl (Upper 
Llandovery) Gotland, Sweden. (Possibly a young strophomenid). 

Strophomenar pectenoides Andreeva in Nikiforova & Andreeva 1961 : 184, pl. 39, 
figs. 1-6. Middle Llandovery, Siberian Platform, U.S.S.R. 

Strophomena lindstronu Gagel 1890 : 43, pl. 3, fig. 12, Upper Silurian, east Baltic. 
(May be a davidsoniacean). 


Discussion. Unfortunately the genera of Upper Ordovician Strophomenidae 
have not yet been evaluated as a whole, and several are not yet comprehensively 
illustrated. It is probable, however, that the fairly compact group in the Silurian 
may be classified together in one genus to include all species not in Pentlandina 
or the Leptaeninae. All these species are resupinate and have a distinctive irregu- 
larly costate ornament, at least in the early Silurian. In addition, their internal 
characters, although often dissimilar at the specific level, clearly indicate their 
congeneric nature. 

The new genus here erected to include these species is placed in the Furcitellinae, 
mainly owing to the similarities with Furcitella Cooper 1956 itself, particularly in 
the ornament and internal morphology, but the Chazy genus is biconvex and has 
a large foramen. Whether the two subfamilies Strophomeninae and Furcitellinae 
really require separation is another matter; the division (Williams 1965) seems to 
have been made mainly on ornamental grounds. In fact, although they are here 
left in separate subfamilies, Katastrophomena shows much resemblance to Stropho- 
mena itself in morphology, especially shape, differing mainly in the presence of 
dental plates and in the ornament, although, as mentioned above, Katastrophomena 
has end members with differentiated parvicostellae. 

The only other strophomenid with which the new genus may be compared is 
Microtrypa Wilson 1945, from the Upper Ordovician of Ontario, Canada, which is 
particularly poorly known, but which appears to differ in ornament and brachial 
interior. 

In the British Llandovery there are thus three species, K. woodlandensis and its 
subspecies geniculata, K. scotica and Kk. penkillensis, each of which will now be 
reviewed. 


STROPHOMENACEAN BRACHIOPODS 295 


Katastrophomena woodlandensis (Reed) 
(Pl. 2, figs. I-10) 
1883. Stvophomena antiquata (J. de C. Sowerby); Davidson : 193, pl. 15, figs. 12-14. 
1917. Strophomena antiquata (J. de C. Sowerby) var. woodlandensis Reed : 902, pl. 18, figs. 20, 
21, pl. 19, figs. 1-5. 
1949. Strophomena woodlandensis Reed Bancroft : 11. 
1951. Stvophomena aff. woodlandensis Reed; Williams : 118, pl. 7, fig. 4. 


Diacnosis. Katastrophomena with coarse, irregular costae, variable shape, and 
variable brachial internal characteristics. 


DeEscrIPTION. Exterior. Variably resupinate, ranging from flat to almost 
geniculate. Ornament of thick irregular costae of subequal size. New costae 
arise mainly by intercalation, but sometimes by branching. Prominent growth lines 
seldom developed. Large interarea. Delthyrium completely closed by large 
pseudodeltidium and chilidium. 

Pedicle interior. Straight hingeline with prominent teeth which form the posterior 
end of a pair of muscle-bounding ridges of variable shape but which generally curve 
inwards without meeting anteriorly. Median septum variably developed, on either 
side of which are faintly impressed blade-like adductor muscle scars inside the more 
strongly developed diductor scars upon which may be seen both faint concentric 
growth lines and also radiating striae. Fairly thick shell, particularly posteriorly, 
but large taleolae not developed. 

Brachial interior. Strong pair of widely divergent socket plates quite separate 
from the small erect bilobed cardinal process. Very variable minor platform and 
muscle area structures (compare Pl. 2, fig. 6, 8, 9). A median septum is usually 
present, which bifurcates to a greater or lesser degree, trans-muscle septa are occa- 
sionally present. 


LectotyPE, here selected. B 54490, a pedicle valve, figured by Reed (1917, pl. 
18, fig. 21) from the Middle Llandovery of Woodland Point, Girvan, Ayrshire, 
Scotland. Gray Collection. 


DIMENSIONS (in cm.—all specimens from Woodland Point) 


If WwW. 
B 54490 Lectotype. Pedicle valve . Pay Bron 
B 73012 Brachial valve . 3 : 2°05 SielGy7/ 
BB 31420 Brachial valve . ; : 1°54 2°25 
BB 31422 Brachial valve. : : 1-78 2°27 


Discussion. There is a large amount of variability in Katastrophomena wood- 
landensis, particularly in two respects; the degree of valve convexity, and the 
development of internal brachial structures. Both points may be seen in Pl. 2; 
where figs. 5-7 show specimens in which the valve direction has changed in the 
median plane by more than go degrees, whereas figs. 8 and 9 show specimens which 
are only slightly concave. Similarly the contrast in the brachial interiors between 
figs. 8 and g is self-evident. 


296 BRITISH LOWER SILURIAN 


K. woodlandensis is not common except at the type locality, but the species is 
also present in the Middle Llandovery of the type area. Two specimens have been 
found, SMA 30006 (Williams 1951 : 118, pl. 7, fig. 4) and BB 31409, collected by 
the author from B; mudstones in a small disused roadside quarry [Grid Ref. SN/ 
760 300]. 

A subspecies has also been erected, K. woodlandensis geniculata {Bancroft 1949 
nom nud.| Williams (1951 : 117, pl. 7, figs. 5-7), whose type specimens are refigured 
here for convenience (pl. 3, figs. 1, 2). This is another rare form from C, beds in 
the Llandovery area. It is best left as a separate subspecies, as, although the 
brachial valve could well be identified as K. woodlandensts (s.s.), the form of the 
pedicle muscle field shows some affinity with K. scotica described below. Further 
collecting at the type locality has failed to produce more material. 

The chief differences between K. woodlandensis and K. scotica are in the shapes 
of the pedicle muscle field and bounding ridges and in the stronger median septum 
usually present in Kk. scotica. The chief difference between these two species and 
K. penkillensis les in the differentiated ornament of the latter. 


Katastrophomena scotica (Bancroft) 


(Pl. 3, figs. 3-9) 


1871. Strophomena antiquata (J. de C. Sowerby); Davidson pars : 299, pl. 44, figs. 21, 22 only. 
1949. Strophomena scotica Bancroft : 12, pl. 1, figs. 4, 5, non fig. 3. 

1949. Strophomena scotica var. alveata Bancroft : 13, pl. 1, figs. 6, 7. 

1951. Stvophomena scotica Bancroft; Williams : 116, pl. 7, figs. 1-3. 


Diacnosis.  Katastrophomena with irregular costae. Pedicle muscle field 
diamond-shaped posteriorly with bounding ridges drawing out anteriorly to become 
sub-parallel in extreme cases. 


DEscRIPTION. Exterior. Variably resupinate. Ornament of thick, irregular 
costae of subequal size. New costae arise by bifurcation and intercalation. Promi- 
nent concentric growth-lines often developed. Large interarea, with at least a 
small pseudodeltidium and possibly a large, entire one. Large chilidium. 

Pedicle interior. Straight hingeline with prominent teeth which form the posterior 
end of a pair of variably developed muscle bounding ridges of curved to diamond 
shape, not meeting anteriorly, but sometimes drawn out and extending sub-parallel 
for a short distance anteriorly. Weak median septum running from the apex to 
approximately the ends of the muscle bounding ridges. On either side of this 
septum are sometimes impressed the pair of small blade-like adductor muscle scars. 
Strongly impressed diductor muscle scars on which concentric growth lines are 
often seen. 

Brachial interior. Large pair of strongly divergent socket plates on either side 
of, and distinct from, the erect bilobed cardinal process. Between the lobes is 
sometimes preserved a small thin blade. Median septum usually strong, variably 
bifurcate. Other structures very variable, trans-muscle septa and muscle bounding 
ridges are sometimes weakly developed. 


STROPHOMENACEAN BRACHIOPODS 207 


LecToTyPE, here selected. SMA 32194, a pedicle internal mould, figured Ban- 
croft (1949, pl. 1, fig. 4) from the Gasworks Mudstone (Lower Llandovery), cutting 
opposite entrance to gasworks, Haverfordwest, Pembrokeshire. Turnbull Collection. 

DIMENSIONS (in cm.—all specimens from type locality) 

Il. Ww. 
-62 approx. 3:7 
46 approx. 3°5 


SMA 32194 Lectotype, pedicle valve 
SMA 32193 Pedicle valve 

BB 31435 Pedicle valve 2 3°05 
BB 31412 Brachial valve : 35 approx. 2°8 
BB 31443 Brachial valve . 3 0-90 122 


no Ww WN N 


Discussion. The second specimen figured by Bancroft has been chosen as 
lectotype because the first (1949, pl. 1, fig. 3) is the counterpart to the figured ex- 
ample of ‘ Strophomena’ agrestis from the Slade Beds (SMA 32040), and was pre- 
sumably illustrated as S. scotica in error. Bancroft also erected a variety, S. scotica 
var. alveata, without giving any differences from the nominal subspecies. As the 
localities are the same and the types of both subspecies virtually identical (refigured 
here Pl. 3, figs. 4-8) and within the range of variation found in the Gasworks Mud- 
stone, no subspecies of K. scotica seem necessary. 

Williams (1951 : 116) selected a specimen from the Gasworks Mudstone of the 
Frolic section as type for the species, but as this is not one of Bancroft’s originals 
the selection is not valid. Williams’ specimen (refigured here Pl. 3, fig. 9) is, how- 
ever, clearly conspecific with the type material from the entrance to the gasworks 
at Haverfordwest. 


Katastrophomena penkillensis (Reed) 
(Pl. 4, figs. 1-6) 


21871. Strophomena antiquata (J. de C. Sowerby); Davidson pars pl. 44, fig. 5 only. 
1917. Stvophonella penkillensis Reed : goo, pl. 18, figs. 11-14. 


Diacnosis. Katastrophomena with differentiated parvicostellate ornament. 


DeEscripTIon. Exterior. Gently resupinate. Ornament of fairly fine differen- 
tiated parvicostellae, the smaller type mere threads. New ribs arise by intercala- 
tion. Large ventral interarea, but smaller on brachial valve than other species of 
the genus. No information on extent of pseudodeltidium. Chilidium present. 
Occasional prominent growth lines sometimes seen on valve exterior. 

Pedicle interior. Straight hingeline with prominent teeth which form the posterior 
end of a pair of muscle bounding ridges of approximately diamond shape, although 
they do not meet anteriorly. Median septum running from the apex to a position 
level with, or just anterior to, the ends of the muscle bounding ridges. On either 
side of the anterior end of the septum are a pair of bladelike adductor scars, which 
themselves may run anterior to the end of the bounding ridges. Diductor scars 
strongly impressed, sometimes with radiating striae and concentric growth ridges. 
Shell of variable thickness with large postero-median taleolae not developed. 


298 BRITISH LOWER SILURIAN 


Brachial interior. Fairly straight socket plates widely divergent. Normal erect 
bilobed cardinal process. Variably developed muscle field structures; trans-muscle 
septa sometimes seen (Pl. 4, fig. 3, but not in Pl. 4, fig. 1). Broad, faint platform 
between two more or less circular muscle scars which are weakly impressed. 


LEcTOTYPE (here selected) B 73013, a brachial internal mould, figured by Reed 
(1917, pl. 18, fig. rr) from the Upper Llandovery of Bargany Pond Burn, Girvan, 
Ayrshire, Scotland. Gray Collection. 


DIMENSIONS (in cm.—all specimens from Bargany Pond Burn) 


ie Ww. 
B 73013 Lectotype, brachial valve . H+57 Ze gA 
BB 31432 Brachial valve . ; : Ty approx. 2°3 
BB 31472 Pedicle valve : E } I+ 40 2:86 


Discussion. Despite the localities being given by Reed as (1) Penkill (2) Bargany 
Pond Burn, all his figured specimens come from Bargany Pond Burn, where the 
species is, however, rare. Reed put the species into Strophonella as he described the 
hingeline as ‘ finely crenulated’, but there is no doubt that the hingelines of the 
specimens to hand, which include all Reed’s syntypes, are smooth. It is surprising 
that Reed made this mistake, especially as Davidson had already labelled some of 
the specimens as S. antiquata (fide Reed 1917 : gor, no Davidson label is with the 
type lot today). 

Katastrophomena penkillensis also occurs rarely in the higher Llandovery horizons 
in Shropshire, for example a pedicle valve (BB 31408) from the Minsterley Formation 
(pl. 4, fig. 6) and a brachial valve from the Purple Shale of the Onny River, GSM 
11693. 

Thus so far the species seems confined to the top half of the Upper Llandovery, 
and to judge both from their ornament and general aspect, it is probable that the 
Wenlock species of the genus were derived direct from some earlier form such as 
K. woodlandensis rather than from K. penkillensis, despite its wide geographical 
range. 


Katastrophomena sp. 
(Pl. 4, figs. 7, 8) 


In the material from Shropshire there are, in addition to the specimens of K. 
penkillensis from the upper beds, two brachiopods referable to Katastrophomena 
from the lower horizons in the northern Longmynd-Shelve outcrop. These consist 
of a pedicle valve from the Venusbank Formation of The Corners, near Betton 
(Grid Ref. SJ/314 025] and a brachial valve from the Bog Quartzite of Bog Mine 
[Grid Ref. SO/3510 9815]. The latter is poorly preserved (BB 31451, Pl. 4, fig. 7), 
but clearly shows the furcitellinid bifurcation of the median septum. The pedicle 
valve (BB 31407, Pl. 4, fig. 8) is a large specimen for the genus and has a more 
angularly pentagonal muscle field than the contemporary KX. woodlandensis geniculata, 
perhaps more similar to some specimens of Kx. scotica from the Lower Llandovery ; 


STROPHOMENACEAN BRACHIOPODS 299 


however the short median ridge does not extend anteriorly of the muscle bounding 
ridges as in the latter species. 

There is no doubt as to the generic identity of these Shropshire specimens, and 
thus they are provisionally described here until more material comes to light. Both 
specimens show marked differences from the named species of Katastrophomena. 
It is noteworthy that no material ascribable to this genus has so far come to light 
in any part of the southern Welsh Borderland. 


Subfamily LEPTAENINAE Hall & Clarke, 1894 


The relationships and status of the leptaenids have been discussed above under 
the heading of the superfamily. Three genera attributable to the subfamily have 
been found in the British Lower Silurian, Leptaena, Cyphomena and Mackerrovia 
gen. nov. A fourth genus, Bellimurina, is represented by a single specimen. It is 
possible that some species here treated as Leptaena might be put into such later 
genera as Bracteoleptaena Havlicek 1963 from the Bohemian Wenlock, but in the 
Llandovery the variation is not enough to separate such species from Leptaena 
itself. 


Genus LEPTAENA Dalman, 1828 


Type species. L. rugosa Dalman 1828 from the Upper Ordovician Dalmanitina 
Beds of Fa dalaberg, Vastergotland, Sweden. A lectotype was selected and the 
species figured by Spjeldnaes (1957, p. 173, pl. 7, figs. 1, 2, 4), and also by Williams 
(1965, fig. 252, figs. 5a, 5b). 

The species problem in Leptaena seems more acute than in most other genera of 
brachiopods. After the mid-Ordovician radiation, the subfamily Leptaeninae grew 
smaller in terms of generic numbers, and thus by Llandovery times the genera were 
reduced to approximately five, and all save Leptaena itself are rare and sporadic. 
On the other hand there is some variation in the form of Leptaena between nearly 
every locality in which one finds it. This bears out the assertion of Imbrie (1956, 
p. 219): ‘ Study of living populations has shown that if sufficiently rigorous methods 
are employed, significant morphological and genetic differences between two popu- 
lations can be demonstrated. Hence species and subspecies must be considered 
as collective categories, in the sense that they are composed of local populations no 
two of which are identical.’ 

Thus a very large number of specific or subspecific names could have been erected 
in the present work, but these would have served only as a smokescreen to hide the 
basic truth of the ‘ Leptaena rhomboidalis’ concept. Here was a successful stock, 
essentially unchanged from the Ordovician to the Carboniferous, which remained 
firmly established in an apparent variety of ecological niches. 

However there are some differences upon which species have already been erected, 
and in many of these cases the differences do persist in many populations from 
many localities. Thus their taxonomic expression is a positive step towards their 
recognition and understanding. 


GEOL. 15, 6. 31 


300 BRITISH LOWER SILURIAN 


Havlicek (1968) has referred several Silurian species to Leptagonia on the grounds 
that their morphogeny has proceeded nearer that genus than to typical Leptaena. 
In this paper all the Silurian forms are retained in Leftaena until the Devonian and 
Carboniferous stocks become better known. 

There now follows a list of previously erected species of Leptaena of Ashgill, 
Llandovery and Wenlock age, followed by a list of species previously referred to 
the genus, but which are here considered distinct from it. 

Ashgill and Silurian species assigned. 

Leptaena rugosa Dalman 1828 : 106, pl. I, fig. 1. Dalmanitina Beds (Ashgill) of 
Vastergotland, Sweden. 

Anomites rhomboidalis Wahlenberg 1821 : 65. ?Wenlock of North German drift. 

Producta depressa J. de C. Sowerby 1823 : 86, pl. 459, fig. 3. Wenlock Limestone 
of Dudley. 

Leptaena tenuistriata J. de C. Sowerby im Murchison 1830 : 636, pl. 22, fig. 2. 
Wenlock of Marloes Bay, Pembrokeshire. 

Leptaena depressa var. vulgaris Barrande 1848 : 84, pl. 22, figs. 6, 7. Wenlock/ 
Ludlow of Bohemia, Czechoslovakia. 

L. quadrilatera Shaler 1865 : 65. Ellis Bay Formation, Anticosti Island, Canada. 

L. schmidti Gagel 1890 : 50, pl. 5, fig. 28. Lyckholm Fm (Upper Ordovician) 
East Baltic. 

L. richmondensis Foerste 1909 : 211, pl. 4, fig. 10. Richmond Group, Ohio, U.S.A. 

L. richmondensis var. precursor Foerste 1909 : 211, pl. 4, fig. 11. Richmond 
Group, Ohio, U.S.A. 

L. rhomboidalis ‘ var. B’ Reed 1917 : 872, pl. 13, fig. 1. Whitehouse Group, 
Girvan, Ayrshire. 

L. rhomboidalis ‘var. y’ Reed 1917 : 872, pl. 13, figs. 2, 3. Drummuck Group, 
Girvan, Ayrshire. 

L. rhomboidalis ‘ var. 6’ Reed 1917 : 872, pl. 13, fig. 4. Mulloch Hill Sandstone 
(Lower Llandovery), Girvan, Ayrshire. (Here described as L. valentia mullochensis.) 

L. rhomboidalis ‘ var. €’ Reed 1917 : 872, pl. 13, figs. 5, 6, non fig. 7. Woodland 
Point (Middle Llandovery), Girvan, Ayrshire. (Here described as L. valentia sp. 
nov.) 

L. rhomboidalis var. nana Chernychev 1937 : 67, pl. 2, figs. 16-18. Wenlock of 
Mongolia. 

L. zeta Lamont 1947 : 200. Penkill Group (Upper Llandovery), Girvan, Ayrshire. 

L. haverfordensis (and var. contracta) Bancroft 1949 : 6, pl. I, figs. 18-24. Gas- 
works Mudstone (Lower Llandovery), Haverfordwest, Pembrokeshire. 

L. valida Bancroft 1949 : 6, pl. 1, fig. 25. Upper Llandovery (C,), Llandovery, 
Carmarthenshire. 

L. urbana Bancroft 1949 : 6, pl. 2, figs. 1, 2. Upper Llandovery (C,), Llandovery, 
Carmarthenshire. 

L. elongata Bancroft 1949 : 7, pl. 1, figs. 26, 27. Upper Llandovery (C,), Llan- 
dovery, Carmarthenshire. 

L. quadrata Bancroft 1949 : 7, pl. 1, figs. 28-30. Upper Llandovery, The Frolic, 
Haverfordwest, Pembrokeshire. 


STROPHOMENACEAN BRACHIOPODS 301 


L. ? tennesseensis Amsden 1949 : 54, pl. 5, figs. 11-15. Brownsport Formation 
(Wenlock/Ludlow), U.S.A. 

L. delicata Amsden 1949 : 55, pl. 5, figs. 11-15. Brownsport Formation (Wenlock/ 
Ludlow), U.S.A. 

L. oklahomensis Amsden 1951 : 85, pl. 16, figs. 29-35. Henryhouse Formation 
(Wenlock/Ludlow), U.S.A. 

L. acuteplicata Sokolskaya 1954: 60, pl. 4, figs. 1-4. Porkuni Stage (Upper 
Llandovery), Estonia, U.S.S.R. 

? Productus twamleyir Davidson 1848 : 315, pl. 3, fig. 1. Wenlock Limestone, 
Dudley, Worcestershire. [The original specimen is not now to be found, but David- 
son (1871 : 282) later put the species into synonymy with L. rhomboidalis. | 


Species excluded from Leptaena 


Leptaena sinuosus and L. parvula Kindle 1915. See Pentlandina. 

L. wisgoriensis Lamont & Gilbert 1945. See Cyphomena. 

L. centervillensis Foerste 1923. Brassfield Limestone, Ohio. 

L. julia (Billings 1862). See Cyphomena. 

L. loveni de Verneuil 1848. See Pentlandina. 

L. bella Williams 1951 : 119, pl. 7, figs. 14, 15. Middle Llandovery, Llandovery. 
Probably an undescribed genus, but the small amount of material at present avail- 
able does not warrant redescription. 


Three groups within Leptaena are recognizable in the British Llandovery. 

(a) Large species with more or less oval-sided pedicle muscle scars. 

(b) Large species with more or less parallel-sided pedicle muscle scars. 

(c) Small species, which as at present known are a rather less well-knit group than 
either of the other two, and which will probably be found to be an amal- 
gam of further groups when more material becomes available. 

In the Lower and Middle Llandovery the first two groups of species seem to have 
been confined to the Scottish area and the Anglo-Welsh area respectively, and this 
remains substantially true for the Upper Llandovery, but in late Upper Llandovery 
time there was some admixture of the two groups; thus rare L. zeta occurs in the 
Purple Shale of Shropshire, and the leptaenid found in Deerhope Burn has the oval 
muscle-scar outline. 

The first two groups could thus have shared a mutual ecological niche, as they 
have not so far been found occurring together. On the other hand, representatives 
of the third group, the small species, do sometimes occur with members of one or 
other of the larger groups, examples of this being at Woodland Point, Girvan, where 
L. valentia and L. reedi occur side by side in apparent harmony, and at locality 
H-G-A in the Malverns where L. contermina and L. zieglert also occur together. 
Thus at least two separate ecological niches may be inferred for species of Leptaena 
in level bottom communities at this time, although for the most part only one or 
other of them was occupied, and the genus is absent from many localities. 

Whether this scheme holds good for other parts of the world during the Lower 
Silurian has not yet been established. The only foreign species of Leptaena so far 


302 BRIELLE WO We Re Ser WRT AWN: 


described from beds of Llandovery age, L. acuteplicata Sokolskaya 1954 from 
Estonia, has not yet been illustrated with interior views, so that its relationship 
with British species remains unknown. 

Some consideration has been given to the possibility of formal subgeneric recog- 
nition of the three groups, but this has been withheld as taxonomic splitting of this 
kind does not seem justified in a generic group which remains extremely well-knit, 
and whose phylogeny is at the moment not completely understood, although some 
relationships are clear. Another possibility would be to have one species name for 
each of the groups, with various subspecies, but this would unite the various small 
forms of the third group under one specific name, which would certainly obscure the 
true situation, in which most of them are definitely more than subspecifically 
separable. 

The British Llandovery species will now be described in the three groups as 
follows: 


(a) L. martinensis sp. nov., L. haverfordensis Bancroft 1949, L. valida Bancroft 
1949, L. urbana Bancroft 1949, L. contermina sp. nov. 

(b) L. valentia sp. nov., L. valentia mullochensis subsp. nov., L. zeta Lamont 1947. 

(c) L. veedi sp. nov., L. ziegleri sp. nov., L. quadrata Bancroft 1949, L. purpurea 
sp. nov. 


Their possible phylogeny is shown in Text-fig. 1. 


Upper Llandovery 


L. zeta 
C4 -6 


L. purpurea L. ziegleri 


L. urbana | L. quadrata 


Upper Llandovery 


Cy _3 L.contermina Y 

L. valida | 

! 
Middle Llandovery L. valentia L.reedi 

L, haverfordensis 
Lower Llandovery | L. valentia 
L. martinensis mullochensis 
FiG. 1. 


Leptaena martinensis sp. nov. 
(Pl. 4, figs. 9-13, Pl. 5, figs. 1-3) 
21949. Leptaena martini Bancroft : 6, non. pl. 1, fig. 18 nomen nudwn. 


Diacnosis. Leptaena with strong rugae and well defined ornament. Poorly 
developed muscle bounding ridges of variable shape. 


DESCRIPTION. Exterior. Shape semicircular to quadrate with alae. Genicu- 
lation between 70 and go degrees. Ornament of well-defined, subequal parvicos- 


STROPHOMENACEAN BRACHIOPODS 303 


tellae. Rugae strong with a particularly large ruga at the knee. Small interarea 
with delthyrium mainly closed by a small chilidium. No information on the foramen, 
but probably small. 

Pedicle interior. Widely divergent teeth with fairly prominent thin dental plates. 
Muscle bounding ridges are poorly developed for the genus and of variable shape, 
sometimes oval, sometimes angular; they do not meet anteriorly. No information 
on the shape of the adductor scars which are not impressed at all on the material 
to hand. No median septum. Central talaeolae, though not large, are more 
prominent than on the trail. 

Brachial interior. Large divergent cardinal process lobes, mounted on a platform. 
The postero-lateral parts of the latter serve as the anterior ends of the sockets. 
The platform is trilobed anteriorly, partly enclosed subcircular adductor muscle 
scars. Median septum usually absent, but in a few specimens a very faint ridge 
may be seen about halfway to the edge of the disc. Occasional prominent pseudo- 
punctae in the central region outside the muscle field. 


HoLotypPe. SMA 31865 a pedicle valve (both interior and exterior are preserved) 
from Cartlett Beds (Lower Llandovery), St. Martin’s Cemetery, Haverfordwest, 
Pembroke. Turnbull Collection. 


DIMENSIONS (in cm.—all specimens from St. Martin’s Cemetery). Note that 
in all the following measurements of species of Leptaena the term 14 signifies the 
distance from the umbo to the knee measured along the median plane; as the trail 
of the various species differs so much, both in form and angle with the disc, a normal 
measurement of length is meaningless for comparative purposes. 


la W. 
SMA 31865 Holotype pedicle valve : I-50 approx. 3:2 
SMA 31859 Paratype pedicle valve ‘ 0:62 1°22 
SMA 31860 Paratype pedicle valve : 0:97 2°04 
SMA 31864 Paratype brachial valve. 1:68 approx. 3°3 
SMA 31861 Paratype brachial valve. 0°53 approx. 0-9 


Discussion. In his paper, Bancroft (1949 : 6) erected ‘ Leptaena martini sp. nov.’ 
giving St. Martin’s Cemetery as the type locality, but referring the reader to his 
pl. r, figs. 18, 23. These two figures are, in fact, of L. haverfordensis from the 
Gasworks Mudstone of the gasworks, Haverfordwest (SMA 32161 and 40512). Thus 
the species is without illustration, or reference to a previous illustration, and thus 
a nomen nudum, according to the rules of nomenclature. Bancroft mentions two 
species present at the St. Martin’s Cemetery, a large one and a small one, but this 
is not borne out by the material in the Turnbull Collection or in subsequent collections 
made by the author. Possibly Bancroft was misled by the small individuals present 
in the Turnbull Collection, but these are all immature as shown by the lack of 
geniculation (pl. 5, figs. I-3). 

The Cartlett Mudstones are the oldest representatives of the Silurian in South 
Wales, and indeed almost certainly span the Ordovician-Silurian boundary, as the 


304 BRITISH LOWER SILURIAN 


writer has found Tvetaspis at their base (kindly confirmed by Dr. W. T. Dean) in a 
temporary (1965) exposure in the foundations for a housing estate behind St. Martin’s 
Cemetery itself. 

L. martinensis is probably an ancestor of L. haverfordensis, but differs from it 
in the more prominent ornament and rugae, and in the more variably shaped and 
less developed pedicle valve muscle bounding ridges. 


Leptaena haverfordensis Bancroft 


(Pl. 5, figs. 4-15) 


1949. Leptaena haverfoydensis Bancroft : 6, pl. 1, figs. 19-20, 23, 24. 
1949. Leptaena haverfordensis var. contyacta Bancroft : 6, pl. 1, figs. 18, 21-22. 


DiaGnosis. Large Leptaena with oval-sided pedicle valve muscle area. Socket 
plates variably present. 


DEscRIPTION. Exterior. Shape semicircular with alae. Angle of geniculation 
between 75 and go degrees. Ornament of numerous fine but well-pronounced, 
sub-equal parvicostellae. Well-developed regular rugae, of relatively small wave 
length for the genus (observed range on the pedicle valve = 10-15 in adult speci- 
mens). At the knee there is always a prominent ruga and just posterior to this an 
unusually pronounced trough. One or two rugae sometimes seen on the upper half 
of the trail. Medium-sized interarea; no information on foramen, but probably 
small. 

Pedicle interior. Prominent teeth and dental plates merging with muscle bounding 
ridges of oval shape; these flare outwards from the valve floor and sometimes meet 
anteriorly, and sometimes are open. Prominent pair of lanceolate adductor scars 
between the diductor scars which often have prominent radiating striae across them. 
Median septum not developed except as a ridge dividing the muscles. Prominent 
taleolae sometimes developed centrally outside the muscle field. 

Brachial interior. Prominent erect slightly divergent cardinal process lobes 
between widely divergent socket plates. Irregular platform developed often tri- 
lobed anteriorly to enclose the pair of suboral adductor scars. The central lobe 
extends further anteriorly to form a very thin, usually faint, median septum. Pro- 
minent taleolae on the disc outside the muscle field. 


LECTOTYPE, here designated. SMA 32163 a pedical valve (figured Bancroft 1949, 
pl. 1, fig. 20) from the Gasworks Mudstone (Lower Llandovery) opposite entrance 
to the gasworks, Haverfordwest, Pembrokeshire. 


DIMENSIONS (in cm.) ihe W. 
SMA 32163 Lectotype, pedicle valve Dovart approx. 3°5 
BB 31355 __—~Pedical valve 1-60 2-96 
BB 31326 Pedicle valve +54 3°45 
BB 31363 Brachial valve . 1°63 approx. 2:6 
BB 31341 Brachial valve . 1°84 approx. 3°4 


STROPHOMENACEAN BRACHIOPODS 305 


Discussion. Bancroft erected L. haverfordensis var. contracta from the same 
locality, based on a single specimen (SMA 40512) which is refigured here (PI. 5, 
fig. 14). From large collections made from the Gasworks Mudstone, it is clear that 
there are all intergrades between this specimen, with its well impressed musculature 
and vascular system, and the typical form, so that no sub-species seems warranted. 

The species occurs in the Lower Llandovery of Pembrokeshire and also in the type 
area of Llandovery, but has not yet been discovered elsewhere, which is not very 
surprising as these two areas represent the most fossiliferous Lower Llandovery in 
the Welsh area. In Girvan, the same ecological niche was occupied at this time 
by Leptaena valentia mullochensis subsp. nov. 


Leptaena valida Bancroft 
(Pl. 6, figs. 1-5) 


1949. Leptaena valida Bancroft : 6, pl. 1, fig. 25. 
1949. Leptaena elongata Bancroft : 7 pl. 1, figs. 26, 27. 


DiaGnosis. Large Leftaena with oval-sided pedicle muscle field which may be 
bilobed anteriorly. A few larger parvicostellae antero-medianly. 


LectotyPE, here selected. SMA 35690, a pedicle valve, external and internal 
mould (figured by Bancroft 1949, pl. 1, fig. 25) from C, beds (Upper Llandovery), 
O. T. Jones collection, his locality 26 SE/E Ar13, River Sefin, 400 yards south-east 
of Llety’r-hyddod, Llandovery, Carmarthenshire. 


DIMENSIONS (in cm.) la w. 
SMA 35690 Lectotype, pedicle valve. 20 approx. 4°3 
SMA 35691 Pedicle valve . . ‘ 1°83 _— 


Discussion. The specimen of Leptaena valida, one pedicle valve, and the speci- 
mens of L. elongata, two pedicle valves, both come from the same locality, i.e. the 
C, shales full of Stvicklandia lens progressa by the side of the River Sefin, Llandovery. 
All are clearly the same species, but the lectotype has been preserved with its disc 
oblique to the bedding plane, and has thus been distorted to give a greater apparent 
width than the other two specimens. Subsequent collecting at the locality has 
resulted in another crushed pedicle valve, but the brachial valve is still unknown. 

The species is striking in that several parvicostellae are distinctly larger than 
the rest in the antero-median region of the valve, giving an impression of differentia- 
tion over this small area only. 


Leptaena urbana Bancroft 
(Pl. 6, figs. 6, 7) 
1949. Leptaena urbana Bancroft : 6, pl. 2, figs. 1, 2. 


LectotyPE, here selected. SMA 35693 a pedicle internal mould, (figured Ban- 
croft 1949 pl. 2, fig. 1) from C, Beds (Upper Llandovery), O. T. Jones collection, 


306 BRT Se OWE Ra Sree) Onkole AGN 


his locality 27 NW/E A8, quarry 500 yards north-east of Cefn Cerig, Llandovery, 
Carmarthenshire. 


DIMENSIONS (in cm.) la Ww. 
SMA 35693 Lectotype, pedicle valve. approx. 2°5 approx. 4:2 
SMA 35694 Brachial valve . : : 2°25 approx. 4°5 


Discussion. The two specimens figured by Bancroft are the only representatives 
of the species in the Sedgwick Museum and further collecting from the type locality 
has not produced more material. 

The species is distinct in its pedicle muscle field shape and size and in the weak- 
ness and irregularity of its rugae. It thus appears to have a valid specific concept, 
but in the absence of more material, further consideration to it will not be given here. 


Leptaena contermina sp. nov. 
(Pl. 6, figs. 8-13, Pl. 7, figs. 1-11) 
1871. Strophomena rhomboidalis (Wilckens); Davidson, pl. 39, fig. 17 only. 


DiaGnosis. Transverse Leftaena with interior encircling ridges in both valves, 
and regular rugae. 


DEscrRIPTION. Exterior. Mucronate and sharply geniculate. Apart from the 
large ears, the shell shape is approximately semicircular, although rather transverse. 
Equally parvicostellate ornament, with ribs increasing slightly in size anteriorly. 
Occasionally new ribs arise either by intercalation or more commonly by bifurcating 
(OUM Cg153 shows both methods on a single brachial valve, an external mould). 
Rugae regular and continuous. The number of rugae on the disc varies between 
six and ten within a population. The geniculation occurs at different lengths 
within a population, but usually between I-0 and 1-4 cm. The angle between the 
disc and trail is between 75 and go degrees. Open delthyrium, prominent chilidium. 
The pedicle foramen has not been observed on any specimen. 

Pedicle interior. Teeth and dental plates small for the genus and fused to a small 
anterior extension of the hingeline. Large, prominent and evenly curving muscle 
boundary ridges, nearly meeting anteriorly and fusing posteriorly with an extension 
of the dental plates. A small median ridge divides the lanceolate adductor scars, 
which are usually very poorly impressed. In some specimens, the diductors com- 
pletely enclose the adductors, in others they just fail to do so. Striae are developed 
on the muscle field, particularly on the diductors. The more coarsely pustulate 
disc and some of the trail are bounded by a nearly semicircular ridge which runs 
round the trail anteriorly but laterally crosses the geniculation and merges posteriorly 
with the hingeline at a low angle near the dental plates. The internal reflection 
of the ornament is much stronger outside this ridge. Coarse pseudopunctae postero- 
medianly, except on the muscle field, but not so prominent as in the brachial valve. 

Brachial interior. Cardinal process lobes prominent, between them a much 
smaller narrow blade-like process. Socket plates variably developed and widely 
divergent, with rarely-preserved striae on their anterior side. Running anteriorly 
and laterally is a three pronged platform which bounds the posterior edge of the 


STROPHOMENACEAN BRACHIOPODS 307 


adductor scars, and the middle prong of which divides them, forming a short, broad 
median ridge. This line is marked discontinuously anteriorly as a fine ridge until 
near the edge of the disc, and in many specimens is more pronounced near its anterior 
end. As with the ventral valve a ridge runs laterally from the hingeline posterior 
of the sockets to the edge of the disc, but instead of crossing the geniculation as 
with the pedicle valve, it stays on its edge, thus making a wall on the anterior edge 
of the brachial valve which is not reflected on the exterior. Except in the muscle 
field, there are prominent pseudopunctae which are random posteriorly, but anteriorly 
are arranged in lines parallel to the external ornament. They are smaller and less 
well defined outside the encircling ridge. 


HoLotyPe. OUM Cor168 a pedicle valve from the Venusbank Formation (Middle 
Llandovery), Hope Quarry, Shropshire. Grid Ref. SJ/3551 0208. Author’s col- 
lection. 


DIMENSIONS (in cm.) la w. 
OUM Co168 Holotype, pedicle valve Hope Quarry aT 2°24 


OUM Co155_ Paratype, brachial valve Hope Quarry iKop mE — 

OUM Cro50r Paratype, brachial valve Bog Mine Teel 2°90 
BB 31280 Paratype, pedicle valve Bog Mine 1°34 2:81 
BB 31289 Paratype, pedicle valve Bog Mine I+ 24 2:46 


Discussion. There is no mistaking this species from any yet described. It is 
much more transverse than most species of Leptaena, and the rugosity is much 
more regular than average, yet not obscuring the ornament. As may be seen from 
the illustrations, there is some variation of the muscle pattern and relative dimen- 
sions, but the species is extremely homogeneous between the various localities. 

Its nearest probable relative is L. haverfordensis from the Gasworks Mudstone, 
which it resembles in the general configuration of the muscle pattern (except in the 
strength of the adductor scars), but it does not have the raised rim to the disc of 
that species, nor is the rugae pattern the same. From L. valida and L. quadrata 
and L. urbana, all from the Upper Llandovery, it differs in diductor muscle con- 
figuration, rugae pattern, and also in ornament, the first two species having more 
prominant costellae near the median plane, and the third being almost without 
ornament. From the later, Wenlock, species it differs in the relative shortness and 
regularity of its trail, the presence of the ventral encircling ridge, and the less massive 
teeth and chilidium. 

In Shropshire the species is confined to the Bog Quartzite and Venusbank Forma- 
tion. It also occurs in the Cowleigh Park Beds of the Malverns, the Wych Beds 
of the Malverns and the Yartleton Beds of May Hill, the last two occurrences being 
substantially the younger. 


Leptaena valentia sp. nov. 
(Pl. 8, figs. 1-8) 
1917. Leptaena rhomboidalis (Wilckens) var. ¢ Reed : 872, pl. 13, figs. 5, 6 non fig. 7. 


Diacnosis. Large Leptaena with sub-parallel muscle bounding ridges. 


308 BRITISH LOWER SILURIAN 


DEscRIPTION. Exterior. Shape semicircular with more or less prominent alae. 
Geniculation between 70 and go degrees. Ornament of subequal parvicostellae, 
which arise by bifurcation or intercalation. Rugae fairly regular, with a particularly 
large ruga developed at the knee. Medium-sized interarea with prominent growth 
lines. Delthyrium almost entirely closed by the large chilidium, but there is a very 
small pseudodeltidium at the delthyrial apex. Foramen not seen, but probably 
small and closed. 

Pedicle interior. Fairly small grooved teeth and dental plates for the genus, the 
latter joined to a pair of strong muscle bounding ridges which flare outwards from 
the valve floor. The form of the bounding ridges is variable, but they usually 
diverge widely posteriorly with the socket plates, then change direction sharply by 
up to 45 degrees becoming subparallel, continuing anteriorly until they merge with 
the valve floor from between half and two-thirds way to the knee. The two bounding 
ridges never meet. Very small median ridge on either side of which are the poorly 
impressed lanceolate adductor scars. The diductor muscle scars are strongly im- 
pressed within the bounding ridges and often have striae impressed upon them. 
Coarsely pustulate in the central region of the valve, outside the muscle area. 

Brachial interior. Prominent, erect, bilobed cardinal process, the two lobes 
diverging slightly laterally. Immediately anterior to these is a prominent platform 
consisting of a pad of secondary calcite. The posterior edge of the pad on either 
side of the cardinal process forms the anterior edge of the sockets and has grooves 
to fit the teeth. The anterior edge of the pad is trilobed, forming half or more of 
the boundary of the roughly circular adductor muscle scars. The adductor scar 
area has various secondary ridges, but they are never so well developed as to form 
trans-muscle septa. Completely anterior of the muscle field there is usually a very 
fine short median septum. As with the pedicle valve the anterior is very coarsely 
pustulate, the individual taleolae standing up to 0:5 mm. above the valve floor. 


HoLotyrPe. B 73340 a complete shell with both valves (figured Reed 1917, 
pl. 13, fig. 5) from the Middle Llandovery of Woodland Point, Girvan, Ayrshire, 
Scotland. Gray Collection. 

DIMENSIONS (in cm.—all specimens from Woodland Point) 

la Ww. 
B 73340 Holotype, pedicle valve measured 1932 approx. 3:6 
BB 55621 Paratype, pedicle valve E35 2 AQZ, 
BB 55637 Paratype, pedicle valve : 23) 2°74 
BB 55653 Paratype, pedicle valve 0-98 Py; 
BB 55705 Paratype, brachial valve 1-18 2°37 
BB 55706 Paratype, brachial valve : 1°25 3:60 


Discussion. This species is common at the type locality, and seems to have 
been one of the more successful leptaenids in the Llandovery. It is clearly a direct 
descendant of its subspecies L. valentia mullochensts, described below, which inhabited 
the same area in the lower Llandovery. Woodland Point is also of interest in that 
it is one of the localities where both large and small species of Leptaena are found 
side by side, in this case L. valentia and L. reed. 


STROPHOMENACEAN BRACHIOPODS 309 


Leptaena valentia mullochensis subsp. nov. 
(Pl. 8, figs. 9-15) 
1917. Leptaena rhomboidalis (Wilckens) var. 6 Reed : 872, pl. 13, fig. 4. 
HoLotyPe. B 73384, a partly exfoliated pedicle valve figured by Reed (1917, 
pl. 13, fig. 4) from Lower Llandovery beds, Mulloch Hill, Girvan, Ayrshire, Scotland. 
Gray Collection. 


DIMENSIONS (in cm.) la Ww. 
B 73384 Holotype, pedicle valve I*44 approx. 3:2 
BB 31375 Paratype, pedicle valve ao 3°34 
BB 73379 Paratype, pedicle valve : 0°95 I-Q2 
BB 31386 Paratype, brachial valve : 1-28 2°26 
BB 31388 Paratype, brachial valve : 120) 1°94 


Discussion. This form seems best considered as a subspecies of L. valentia as 
the two are very close in most morphological details, particularly in the internal 
structures within both valves. There are, however, various minor differences which 
enables Reed’s separation to be confirmed. Rugae counts on pedicle internal moulds 
give the following results (number of rugae visible up to geniculation). 


Rugae Number Woodland Point Mulloch Hill 


4 2 0) 
5 18 3 
6 15 8 
7 2 5 
8 0) 2 

i = 37) i, == Ite) 


Reed (1917 : 872) noted differences between the two ‘ varieties’ of the angle at 
which the rugae meet the hingeline, but this is not supported by the present inves- 
tigation. The rugae are however, less regular in L. valentia mullochensis than in, 
the typical subspecies, often being interrupted, particularly laterally. 

The pedicle valve length of disc/width ratios of the two subspecies are virtually 
the same, having a mean of 42:8° for Mulloch Hill (n = 21, OR 31-3-57-4) and 
41:9% for Woodland Point (n = 53, OR 29:0-52:8). The variability of the 
pedicle valve muscle field for the whole species is demonstrated by PI. 8, figs. ro, 
23, 14. 

Leptaena zeta Lamont 
(Pl. 9, figs. 1-6) 
1871. Strophomena rhomboidalis (Wilckens); Davidson : 281 pars, pl. 39, fig. 20 only. 
1917. Leptaena rhomboidalis (Wilckens) var. € Reed : 872, pl. 13, figs. 8, 9. 
1947. Leptaena zeta Lamont : 200. 


Diacnosis. Very large Leptaena with mainly parallel-sided muscle area. 


DESCRIPTION. Exterior. Shape semicircular with variably pronounced alae. 
Geniculation between 70 and go degrees, and trail proportionately shorter than is 


310 BRITISH LOWER SILURIAN 


usual for the genus. Ornament of subequal parvicostellae and rugae which are 
usually continuous but are often irregular. Medium-sized interarea with prominent 
growth lines. Delthyrium mainly closed by large chilidium which appears bilobed 
as it wraps round the cardinal process lobes. Small foramen plugged by adventi- 
tious material. 

Pedicle interior. Strong grooved teeth and widely divergent small dental plates, 
the latter joined to a pair of muscle bounding ridges which flare outward from the 
valve floor. The ridges are usually subparallel but occasionally curve inwards 
anteriorly, though never meeting and usually completely open (Pl. 9, figs. 2, 3). 
Very small median ridge sometimes developed in the muscle area between the small 
lanceolate adductor scars, themselves inside the strongly impressed diductor scars 
which often have radiating striae across them. The central area outside the muscle 
field is coarsely pustulate. 

Brachial interior. Strong erect cardinal process lobes very close to the chilidium 
with faint blade between them. The lobes rest on the posterior end of a strong 
platform pad, which is often grooved postero-laterally to act as a socket plate. 
The platform anterior edge is trilobed, surrounding on three sides the pair of promin- 
ent subcircular adductor scars. A faint extension of the central platform sometimes 
extends further anteriorly to become a very small median septum. The central 
area which merges laterally with the platform is coarsely pustulate. 

LEcToTyPE, here designated. B 73355 (the original of Reed 1917, pl. 13, fig. 8), 
a pedicle exterior from Penkill, Girvan. Gray Collection. 


DIMENSIONS (in cm.) ihe w. 

B 73355 Lectotype, 

pedicle valve Penkill TOY, approx. 4°4 
BB 31305 Pedicle valve Penkill 2°29 approx. 4°7 
B 73364 Pedicle valve Bargany Pond Burn 2:38 approx. 5:8 
B 73365 Pedicle valve Bargany Pond Burn 2-10 approx. 5:2 
BB 31469 Pedicle valve Minsterley Lane approx. 2-3 6:58 
BB 31468 Brachial valve Muinsterley Lane 2°05 3°42 


Discussion. This is the largest species of Leptaena found in the British Llan- 
dovery (though not the largest in the Silurian—this is probably the undescribed 
species in the Woolhope limestone). It seems confined to the highest beds at 
Girvan—the Penkill group, and also to the Minsterley Formation of Shropshire. It 
is not common at any locality. 

From the general aspect, particularly the shape of the pedicle and brachial muscle 
field, it is probably a descendant of Leptaena valentia sp. nov. also from the Girvan 
area. 

Leptaena reedi sp. nov. 
(Pl. ro, figs. 1-14) 
1917. Leptaena rhomboidalis (Wilckens) var. e (young shell) Reed : 872, pl. 13, fig. 7. 

Dracnosis. Small Leptaena, transverse, thick shelled, with large area and 
pseudodeltidium. 


STROPHOMENACEAN BRACHIOPODS 311 


DeEscripTiIon. Exterior. Shape transverse with large alae, sometimes quadrate 
anteriorly. Geniculation often more than go degrees with the trail sometimes 
bending back under the disc. Ornament of subequal parvicostellae, coarser on the 
disc than on the trail. Symmetrical rugae on the disc, but no trace on the trail. 
Large interarea, particularly in the pedicle valve. Delthyrium closed partly by 
pseudodeltidium, partly by chilidium. Small supra-apical foramen plugged in most 
specimens. 

Pedicle interior. Strong grooved teeth attached to a pair of distinct bilobed 
muscle bounding ridges which sometimes meet anteriorly, but which are sometimes 
divided by a small median septum. Diamond shaped adductor scars on a ridge 
raised between the triangular diductor scars, which are sometimes grooved. Coarse 
taleolae on the disc outside the muscle field. Thick shell. 

Brachial interior. Erect, posteriorly directed bilobed cardinal process. Raised 
platform with variably developed trans-muscle septa. Short median septum some- 
times developed but often absent in the muscle field. Interior reflection of rugae 
but not ornament. Sharp geniculation usually present, inside which is a well 
developed taleolae field. 


HorotyPe. B 73341, a complete shell (figured by Reed 1917, pl. 13, fig. 7) from 
Woodland Point, Girvan, Ayrshire. Gray Collection. 


DIMENSIONS (in cm.) la w. 
B 73341 Holotype, pedicle valve : 0°51 approx. I°5 
BB 31457 Paratype, pedicle valve : 0°75 1°72 
BB 31461 Paratype, brachial valve : 0:68 1°81 
B 73342 Paratype, brachial valve : 0-66 TEOR Ys) 


Discussion. Reed mistook this species for the young of L. valentia and they 
occur mixed intimately (e.g. Pl. ro, fig. 10) but the two are clearly distinct in nearly 
every feature. 

L. rveedi is rare at the type locality, although the Gray Collection contains about 
thirty specimens, and has not been found elsewhere than at Woodland Point. Its 
affinities are uncertain. No other species of Leptaena resembles it, and the large 
interarea is unique amongst Silurian strophomenids. The brachial muscle field is 
more reminiscent of Cyphomena or some of the strophomenids than of other species 
of Leptaena. 


Leptaena ziegleri sp. nov. 
(Pl. x1, figs. I-5) 


DiaGnosis. Small Leptaena with oval pedicle muscle field, and possessing strong 
socket plates. 


DEscripTION. Exterior. Shape semicircular, occasionally quadrate with small 
alae. Geniculation usually at right angles. Ornament of faint subequal parvi- 
costellae, rugae symmetrical and numerous but faint. Interarea small. Delthyrium 
probably mainly open, but no information on possible chilidium. Foramen not 
seen. 


312 BRITISH LOWER SILURIAN 


Pedicle interior. Prominent teeth and dental plates joined to strong muscle 
bounding ridges. The latter are of oval, almost circular shape, but not quite meeting 
anteriorly. Adductor scars are not seen, diductor scars are poorly impressed 
within the muscle bounding ridges. Faint median septum in one specimen only 
(OUM C4147) otherwise absent. 

Brachial interior. Small, erect, bilobed cardinal process ankylosed to strong pair 
of socket plates. Brachial muscle field not impressed and details of muscalature 
not known. Very faint trace of median septum seen in some specimens only. 
Raised rim at edge of disc. 


HoLotyPe. OUM C4146, a pedicle valve internal mould from the Wych Beds 
(Upper Llandovery), Malvern Hills, Herefordshire. Grid Ref. SO/7612 3811. 


DIMENSIONS (in cm.) la w. 
OUM C4146 Holotype, pedicle valve. 0-64 1°05 
OUM C4147 Paratype, pedicle valve. 0°54 1°25 
OUM C4137 Paratype, brachial valve . 0:58 approx. 1:9 
OUM C4136 Paratype, brachial valve . 0-64 approx. 1-4 


Discussion. The species is known only from its type locality. It is distinctive 
in pedicle and brachial internal structures and in its shape and ornament. The 
species is named after Dr. A. M. Ziegler, who collected the material. 


Leptaena quadrata Bancroft 
(Pl. x1, figs. 6-r0) 
1949. Leptaena quadvata (Reed MS) Bancroft 1949 : 7, pl. 1, figs. 28-30. 


DiacGnosis. Small quadrate Leptaena with many fine rugae. 


DeEscRIPTION. Exterior. Shape quadrate with small but pronounced alae. 
Small trail after geniculation of approximately 80 degrees. Ornament of fine 
symmetrical rugae and faint subequal parvicostellae. Interarea of average size. 
No information on possible pseudodeltidium; small chilidium present. Foramen 
not known, but probably small. 

Pedicle interior. Small divergent teeth joined to variably developed muscle 
bounding ridges. The latter are long and sub-parallel, sometimes merging anteriorly 
with the valve floor (Pl. 11, fig. 6), sometimes swinging round in an irregularly 
bilobed fashion (Pl. 11, fig. 10). A pair of elongate adductor scars between the 
impressed long diductor scars. Median septum absent. 

Brachial interior. Erect bilobed cardinal process. Weak platform posteriorly 
acting as socket plates, anteriorly enclosing weakly impressed adductor muscle field 
of approximately oval shape. Sometimes very thin median septum weakly de- 
veloped. 

LECTOTYPE, here selected. SMA 32437 a_ edicle valve internal and external 
mould (figured Bancroft 1949, pl. 1, fig. 28) from Uzmaston Beds (Upper Llandovery), 


STROPHOMENACEAN BRACHIOPODS 313 
O. T. Jones Collection, ‘ locality K, below path south west of Uzmaston,’ The Frolic, 
near Haverfordwest, Pembrokeshire. 


DIMENSIONS (in cm.) la W. 


SMA 32437 Lectotype, pedicle valve. 0:73 0:86 
SMA 32444 Pedicle valve . : f 0°55 0-86 
SMA 32438 Brachial valve . : : 0-63 I*02 
SMA 32441 Brachial valve . j 0°53 0:93 


Discussion. This species is known only from its type locality where it occurs in 
a slightly crushed greenish siltstone. Its associates are Amp/luistophia whittardi 
Cocks, Pentlandina parva Bancroft, Dicoelosia cf. alticavatus (Whittard & Barker), 
Coolinia sp., Atrypa sp., Eospirifer sp. and Eoplectodonta millinensts (Jones), which 
indicate on balance a Cloyinda community, although no pentamerids have been seen. 

The usual leptaenid in the Welsh Borderland Clorvinda community is L. purpurea 
sp. nov., and Bancroft’s species may be related to it. L. purpurea has, however, a 
completely different muscle field disposition in both pedicle and brachial valves, 
and different overall proportions. It is also larger. 


Leptaena purpurea sp. nov. 
(Pl. 12, figs. 1-6) 
1932. Leptaena sp. nov. Whittard, table facing p. 896. 


DiaGnosis. Small quadrate Leptaena with usually oval-sided pedicle muscle 
bounding ridges. 


DESCRIPTION. Exterior. Shape quadrate with small ears. Sharply geniculate 
with approximately a right angle between disc and trail, but the angle varies between 
obtuse and acute. Ornament of fine, subequal parvicostellae, with new costellae 
arising by intercalation. Rugae cover the whole disc on both valves; they are 
fairly regular and have a small wavelength. Small external rim on the ventral 
knee and a small groove on the dorsal knee. Open delthyrium, large chilidium, 
but rather smaller interarea than is common for the genus. No information on 
the pedicle foramen, except of a very young specimen (OUM C13141) in which it 
is supra-apical and probably, at that stage, functional. 

Pedicle interior. Straight hingeline with open delthyrium flanked by relatively 
large dental plates, considering the small size of the species which are combined in 
part with a raised posterior extension of the muscle bounding ridges. Faint muscle 
grooves often seen on the muscle field. Diductor scars bilobed and surrounded 
laterally by pronounced bounding ridges which in some specimens curve round 
anteriorly to form an w shape, although they do not quite meet in the centre. Small 
lanceolate adductor scars, though seldom seen, are separated by a fine median ridge 
which in a few specimens continues anteriorly of the muscle bounding ridges. In 
completely preserved specimens there is a ridge running about half-way down the 
trail and nearly all the way round it, but postero-laterally crossing the geniculation 
and merging at a low angle with the hingeline, although on many specimens the ridge 
is very faint. Pseudopunctae coarse near the umbo, except where absent in the 


314 BRITISH LOWER SILURIAN 


muscle field. They are apparently randomly distributed near the umbo, but 
antero-laterally they tend to be arranged in lines parallel to both the rugae and the 
ornament. 

Brachial interior. Raised cardinal process with two stout lobes directed ventrally. 
Large chilidium fused close to the base of the cardinal process. Anchor shaped 
platform present, the haft of which forms a median ridge dividing the two pairs of 
oval adductor muscle scars, which are separated from each other by the pair of low 
short ridges running laterally from each side of the haft. Disc surrounded by 
raised rim, which is reflected to a lesser extent by the exterior groove, indicating 
a local thickening of the shell material. Mantle canals visible occasionally (Pl. 12, 
fig. 3) coming from the floor of the disc, up over the rim and fading towards the 
valve margin. No bifurcations seen. Pseudopunctae very noticeable postero- 
medianly, but scarcely visible on rim or trail. 


HoLotyPE. BB 31465, a pedicle internal mould from the Purple Shale (Upper 
Llandovery) of Domas, Shropshire. Grid Ref. SJ/5936 0062. 


DIMENSIONS (in cm.). la 


2 


BB 31465 Holotype, pedicle interior Domas 0°52 I-06 
BB 31466 Paratype, brachial interior Hughley 0-51 T-1O 
OUM Cr2062 Paratype, pedicle interior Onny River 0°54 1-08 
OUM C13480 Paratype, brachial exterior Domas 0°43 I-15 
OUM C13478 Paratype, brachial exterior Domas 0°47 TAN 
OUM C13477 Paratype, brachial exterior Domas 0°45 I+20 
OUM C13482 Paratype, pedicle interior Domas 0-41 0°79 
OUM Cr3141 Paratype, brachial exterior Wall-under-Heywood 0-20 0:29 


Discussion. Although leptaenids are to be found in nearly every collection from 
the Purple Shales, they are never common, but those that do occur are usually 
attributable to this form. The species is small, and thus only strictly comparable 
with L. quadrata Bancroft from the Upper Llandovery of the Frolic, Haverfordwest, 
from which it differs in its larger teeth, encircling muscle ridges and the character 
and strength of the rugae. 

One specimen of a leptaenid of comparable size, 1-35 cm. wide, has been collected 
(Bristol University Museum 12101) from the contemporary Damery Beds (C;) of 
Tortworth by Dr. M. L. K. Curtis. -The specimen, a pedicle valve (PI. 12, fig. 6), 
differs from L. purpurea in the indented shape of the muscle bounding ridges and 
also in the almost complete absence of internal ornament or rugae, but in general 
shape and size it is similar. Without further material, particularly brachial valves, 
any definite attribution seems unwarranted. 


Leptaena sp. 


(Bly 12, tisse 74 8) 


EXTERIOR DESCRIPTION. Shape quadrate and alate. Ornament of subequal, fine 
parvicostellae. Small rugae, uneven round the disc, but giving the illusion of not 


STROPHOMENACEAN BRACHIOPODS 315 


being so. At least eighteen rugae_of subequal wavelength (except near the umbo) 
on the ventral disc and sixteen on the dorsal. Geniculation less than right angles 
on the ventral valve, but the trail curves into a steeper angle, meeting the anterior 
margin at an acute angle with the disc. Small external rim on the ventral knee, 
and small external groove on the dorsal knee. Prominent interarea. Open del- 
thyrium, large chilidium, with growth-lines persisting to the interarea. Small 
foramen about 0:2 mm. diameter. 


Locatity. Purple Shales, ‘near Harley’, Shropshire. 


DIMENSIONS. width = 3-6 cm. approx., length = 1-73 cm., length of disc = 
I:43 cm., height of trail = 1-2 cm. 


Discussion. In the late Professor Whittard’s collection there is one complete 
specimen (BB 31467) of Leptaena which cannot be assigned with confidence to any 
described species, but until interior details are known, to name a new species would 
be premature. Though too big for Leftaena purpurea it is sufficiently close to it 
for the possibility of a sport not to be ruled out completely, despite its large disc 
and overall size. Its shell thickness, interarea, and general proportions are much 
finer and more delicate than the Wenlock L. depressa. It may, however, be related 
to a large, undescribed species of Leptaena present in the Woolhope Limestone 
of Crickley Common, Herefordshire and elsewhere. 


Genus CYPHOMENA Cooper 1956 


TYPE SPECIES. Leptaena homostriata Butts 1942 from the Oranda Formation 
(Middle Ordovician) of Virginia, North America. 

Discussion. When Cooper (1956 : 840) erected Cyphomena he put into it three 
species (and tentatively a fourth), all from the Middle Ordovician of North 
America. Subsequently Williams (1962 : 203) recognized one of them in the 
Scottish Caradocian. These are the only published records. 

The interior disposition and external form of the various species of Cyphomena, 
so well figured by Cooper, leave no doubt of the close relationship between them 
and some species present in the Llandovery. In particular the gradually curving 
pedicle valve and sharply geniculate brachial valve, the proportions and disposition 
of the musculature and denticulation in both valves, and the small curved pseudo- 
deltidium not completely filling the delthyrium, above which is developed a suffi- 
ciently large pedicle foramen for it to be considered functional, are identical in 
Ordovician and Silurian specimens. 

There is, however, one point of difference in that Cooper’s genus ‘ never developed 
the concentric wrinkling of the visceral region ’ (1956 : 841). It is true that complete 
rugae of the type found in Leftaena are not seen in the Silurian forms, but interrupted, 
sometimes zig-zag, rugae between the costellae are often well-developed, for example 
in C. wisgoriensis. This is in contrast to the simple costellae of the Caradocian 
species. This zig-zag type of ornament occurs many times in the Strophomenida 
and must be polyphyletic, perhaps the best-known example being the plectamboni- 
tacean Ptychoglyptus. In addition there occurs ir the Llandovery a form, described 

GEOL. 15, 6. 32 


316 BRITISH LOWER SILURIAN 


below, which apparently lacks ornament of any kind, but has interior and general 
form very close to the Ordovician species. 

Thus to satisfactorily represent the close relationship between all these forms, 
but also to bring out their inherent differences, two new subgenera of Cyphomena 
are proposed here, one, Cyphomenoidea, to include forms with interrupted rugae, 
and the other, Laevicyphomena, to include forms, only one of which is at present 
known, which lack exterior ornament of any kind. 


CYPHOMENA (CYPHOMENOIDEA) subgen. nov. 


DiaGnosis. Cyphomena with parvicostellate ornament, the major ribs interrup- 
ting small, irregular rugae over the whole shell. 


TYPE SPECIES. Leptaena wisgoriensis Lamont & Gilbert 1945. 
RANGE. Llandovery, ?Wenlock Series. 


Discussion. The same type of ornament as appears on Cyphomenoidea may 
also be seen on many species of Pentlandina, for example the contemporaneous 
Pentlandina lovent (de Verneuil 1848) from the Visby Marl of Gotland. It is seen 
again on Strophomena julia Billings 1862 from the Jupiter Formation (Upper Llan- 
dovery) of Anticosti Island, Canada, but in this case illustrations of the interior 
are not available. A topotype in the British Museum (B 76891), a complete shell 
with both valves joined, has the correct profile for the new subgenus, but the species 
may be a strophomeninid and cannot be referred to Cyphomenoidea with confidence 
until the interior is known. 


Cyphomena (Cyphomenoidea) wisgoriensis (Lamont & Gilbert) 
(Pl. 12, figs. 9-12) 


1945. Leptaena wisgoriensis Lamont & Gilbert : 660, pl. 3, figs. 10-14. 
1951. Leptaena wisgoriensis Williams : 119. 


TYPE LOCALITY. Sunken track through Coneygore Coppice, near Alfrick, Wor- 
cestershire [Grid Ref. SO/7464 5111). 


Discussion. A full description of the species may be found in Lamont & Gilbert 
(1945 : 660-662). Although a large collection in the Oxford University Museum 
by Dr. Ziegler from the type locality failed to produce specimens of C. wisgoriensis, 
good material was found at Grid Ref. SO/7430 5152, less than a third of a mile away 
and at the same stratigraphical horizon, and some is illustrated here. A comparison 
of Pl. 12, fig. 10 with pl. 224, fig. 21 of Cooper (1956) reveals that the interior of the 
brachial valves of C. wisgoriensis and C. angulata Cooper are virtually identical, 
apart from the smaller size, more pronounced reflection of the ribbing (or possibly 
pallial sinuses) and slightly larger anterior median ridge of the latter species. In 
particular the distinctive shape of Cooper’s species, with a sharp geniculation and 
raised rim in the brachial valve and much more gentle curve without geniculation 
in the pedicle valve, together with the close similarity of internal structures in both 
valves, pronounce them to be close relatives. 


STROPHOMENACEAN BRACHIOPODS 317 


The major difference between the two lies in the nature of the ornament, as men- 
tioned in the discussion of the genus. All three species described by Cooper have 
more or less equally costellate ornament, whereas C. wisgoriensis has a subequal 
parvicostellate ornament, upon which is superimposed small irregular rugae separated 
from each other by the larger ribs, forming a regular zig-zag pattern (Pl. 12, fig. 12). 

The species has been recognized only from the Wych Beds (C;_, in age) of the 
North Malverns and Ankerdine Hill, but a solitary external mould of a brachial 
valve from the Purple Shale of Hughley, Shropshire, has a similar ornament and 
may tentatively be referred to C. wisgoriensis. 


CYPHOMENA (LAEVICYPHOMENA) subgen. nov. 


DiaGnosis. Cyphomena with no shell ornament. 
TYPE SPECIES. Cyphomena (Laevicyphomena) feliciter sp. nov. 
RANGE. Middle to Upper Llandovery Series. 


Discussion. The new subgenus has as yet only one species attributed to it. 
Although it is fairly certain that the latter has no ornament, it has admittedly been 
found so far only in sandstone matrices, and it is possible that some sort of very 
fine ornament might have escaped detection. 


Cyphomena (Laevicyphomena) feliciter sp. nov. 
(Pl. 12, figs. 13-14, Pl. 13, figs. I-9) 
1932. Styvopheodonta funiculata (M’Coy); Whittard pars, table facing p. 896. 


DiaGnosis. Smooth Cyphomena with laterally concave ridges in the brachial 
valve. 


DeEscrRIPTION. Exterior. Shape trapezoidal, varying sometimes to semicircular, 
particularly in the outline of the brachial geniculation. Sometimes slightly alate. 
Pedicle valve has a gradual convexity, always less than a total of 90 degrees, but 
brachial valve flat apart from its geniculation. No visible ornament, but fine 
growth-lines have been observed on the trail only of a few specimens, and the shell 
surface may be slightly buckled (rugate would be too definite a term) near the 
lateral extremities only. Interarea medium-sized to small for a leptaenid. Small 
chilidium. Functional foramen at apex of pedicle valve, below which is a small 
pseudodeltidium apparently not entirely covering the delthyrium. 

Pedicle interior. Thickened hinge line, the anterior edge of which diverges laterally 
away from the umbo until it reaches the edge of the trail, where it thins and becomes 
flush with the main shell. Prominent dental plates (but short in a dorsal direction) 
diverge at an angle of go degrees or more, and continue anteriorly as muscle bound- 
ing ridges which persist for a short distance in the same direction, but then swing 
through an angle of 60-80 degrees to converge again, though they do not meet. 
Thus the pedicle muscle field is somewhat similar to that of a strophomeninid, 
except when the species becomes gerontic (PI. 13, fig. 7), and an anterior fold connects 


GEOL. 15, 6. 328 


318 BRITISH LOWER SILURIAN 


the two bounding ridges, overriding the median septum which in young specimens 
divides them. Rarely (e.g. Pl. 13, fig. 1) the muscle field presents a rather more 
bilobed appearance, with the median septum poorly developed except anteriorly. 
No trace of pseudopunctae seen. 

Brachial interior. Straight hinge line, to which is fused a pair of widely divergent 
socket plates. Two small cardinal process lobes approximately at right angles to 
the valve floor. Small platform, ending anteriorly with a very short, small median 
ridge, a trace of which may often be seen again in the anterior part of the disc, 
although it is never continuous. From approximately the antero-lateral end of 
the socket plates, and usually separated from them by a short gap, run a pair of 
ridges, subparallel to the median plane but concave outwards. The degree of 
concavity varies, and a small proportion are almost straight. These ridges bound 
the anterior pair of adductor muscle scars, which are particularly elongate. The 
posterior pair are smaller, approximately round, and situated immediately anterior 
of the socket plates. They are occasionally separated from the anterior adductors 
by two poorly-developed small nodes, which are just posterior of the point of closest 
proximity of the two bounding ridges. The geniculation is sharp (in contrast to 
the pedicle valve) and often associated with a marked interior rim, which is not 
reflected on the exterior. No trace of pseudopunctae observed. 

Ho.otyPe. BB 31346, a pedicle valve from the Bog Quartzite of Bog Mine, 
Shropshire [Grid Ref. SO/3510 9815]. Other localities (all in Shropshire): Napp 
Outlier [SO/3493 9922], Josey’s Wood [SJ/3653 0221] and Bank Outlier [SJ/3821 
0418}. 


DIMENSIONS (in cm.) 1 w. 
BB 31346 Holotype, pedicle valve Bog 0:62 I°45 
BB 31345 Paratype, pedical valve Bog 0-74 PF OP 
OUM Co895_ Paratype, pedicle valve Bog 0-70 I-40 
OUM C10988 Paratype, pedicle valve Josey’s Wood 0-78 1°52 
BB 31348 Paratype, brachial valve Bog OF 7 I-96 
OUM Co893 ~Paratype, brachial valve = Bog 0:68 — 
BB 31347 Paratype, brachial valve Bog 0:69 neo 
BB 31352 Paratype, brachial valve Napp Outlier On 7 evan 


Discussion. It is unfortunate that this distinctive species should be preserved 
only in fairly coarse matrices, so that fine details of possible ornament or arrange- 
ment of pseudopunctae cannot be observed. So far the species is confined to the 
Bog Quartzite and Venusbank Formation of Shropshire; only two specimens (OUM 
Crog88 from Josey’s Wood and BB 31354 from Bank Outlier) have been recovered 
from the latter horizon, and the species does not occur above 1 % in any collection. 

C. feliciter is not far removed from C. wisgoriensis and other older species of 
Cyphomena, but differs from them in many ways—the lack of distinctive ornament, 
the development of the brachial ridges, and the general proportions and shape of 
the valves. However there are sufficient characteristics in common, particularly 
the general internal arrangement, the open foramen and small pseudodeltidium, 


SETROPHOMENACEAN BRACHIOPODS 319 


and the geniculation angles in both valves, to enable the new species to be included 
in Cyphomena with a fair degree of confidence. 


Genus MACKERROVIA nov. 


DiaGnosis. Irregularly geniculate leptaenid with long diductor scars in the 
pedicle valve, bounded laterally by high irregular ridges, and partially mirrored in 
the brachial valve by long anterior adductor scars, bounded by less pronounced 
ridges. Shell surface often irregular. Very faint, often invisible ornament of 
differentiated parvicostellae. Pedicle atrophied in adults. 


TYPE SPECIES. Brachyprion arenaceus var. lobatus Lamont & Gilbert 1945 
emended below, the only known species. 


Discussion. Mackerrovia is quite different from any genus yet described, and 
its attribution to the leptaeninids rather than to any other subfamily within the 
Strophomenidae is based mainly upon the geniculation. The most distinctive 
feature is the long muscle scars bounded by high ridges in the pedicle valve (and 
corresponding traces in the brachial valve). This is paralleled only by a homoeo- 
morphic development in the Stropheodontidae, namely Shaleria and to a lesser 
extent some species of Amphistrophia, but in these genera the ridges are much more 
uniform. The present genus is not a stropheodontid, despite its previous ascription 
to Brachyprion, and the whole internal structure is quite different, in addition to 
there being no trace of denticles on the hingeline. As well as possessing the long 
scars, Mackerrovia differs from other leptaeninid and strophomeninid genera in the 
usual absence of rugae and also the highly irregular shell surface, which is more 
reminiscent of some Upper Palaeozoic davidsoniaceans. 

The genus, known so far only from the higher part of the Upper Llandovery in 
the Welsh Borderland, is named after Dr. W. S. McKerrow. 


Mackerrovia lobatus (Lamont & Gilbert) 
(Pl. 13, figs. 10-15; Pl. 14, figs. 1-8) 


1871. Strophomena avenacea {Salter MS] Davidson pars, pl. XLII, figs. 7-8, non fig. 6. 

1945. Bvrachyprion avenaceus var. lobatus Lamont & Gilbert : 667, pl. VI, fig. 6, pl. VII, fig. 2. 

1945. Byvachyprion arenaceus var. geniculatus Lamont & Gilbert : 669, pl. VI, figs. 1-5, pl. VII, 
fig. 3. 

1953a. Brachyprion arenaceus var. geniculatus Lamont & Gilbert; Williams : 23. 


Diacnosis. As for genus. 


Description. Exterior. Shell shield-shaped with no alae. More or less sharp 
geniculation occurs at a variable length (occasionally, e.g. Pl. 13, fig. 15, two geni- 
culations are visible). Shell surface uneven and irregular in detail. Some speci- 
mens show well-developed growth lines. Ornament of extremely faint parvicos- 
tellae with even smaller stripes between them, but this is not seen on most specimens. 
Hingeline straight, but immediately anterior to it the shell often curves up (viewed 
from the posterior) from the umbo, Pseudodeltidium closes the delthyrium flush 


320 BRITISH LOWER SILURIAN 


with the interarea, the latter being of variable size and sometimes scarcely developed 
at all in the brachial valve. No trace of a foramen observed. 

Pedicle interior. Thickened hingeline with medium-sized teeth that protrude 
anteriorly as well as ventrally. Long diductor muscle scars are of irregular shape 
and enclose long adductor scars separated by a small but persistent median ridge. 
Round the scars, posteriorly as an extension of the teeth, are long, high bounding 
ridges of variable shape, subparallel, concave or convex, or a mixture of the three. 
Sometimes they converge anteriorly (Pl. 14, fig.1), sometimes they diverge (Pl. 14, 
fig. 7). They usually double back round the anterior end of the diductors, but are 
always prevented from meeting by the median ridge. Usually the bounding ridges 
are not at right angles to the valve floor, but are directed dorso-laterally. The 
whole muscle area is not always in the median plane, and may be directed anteriorly 
either to right or left. Fairly large pseudopunctae visible on most specimens 
everywhere except on the muscle field. 

Brachial interior. Prominent cardinal process lobes directed ventrally, but 
diverge anteriorly. Long narrow sockets diverge at just over go degrees, bounded 
anteriorly by slender socket plates whose posterior half lies latero-posteriorly, and 
very close, to the cardinal process lobes. The socket is bounded posteriorly by a 
slight elevation of the hingeline. Very weak platform ends anteriorly in a broad, 
weak median ridge dividing the posterior pair of adductor muscle scars. The ridge 
bifurcates and then closes together again, leaving a faint pit (Pl. 14, fig. 5), after 
which it becomes narrow but more pronounced, dividing the anterior adductors 
and continuing, in some cases, nearly to the edge of the disc. No muscle bounding 
ridges near the umbo, but about a third of the way to the trail they suddenly appear, 
to persist strongly anteriorly for 5-10 mm., though never so pronounced as in the 
pedicle valve. Fairly large pseudopunctae visible everywhere except in the muscle field. 


LEcTOTYPE, here selected. GSM 11461, a pedicle valve from Wych Beds (Upper 
Llandovery), Gunwick Mill, Malvern Hills, Worcestershire. 


DIMENSIONS (in cm.). l w. 
Bristol 12143 Pedicle valve . 2-00 157 
Bristol 12144 Pedicle valve . 1°93 2°46 
Bristol 12159 Pedicle valve . 2°42 approx. 2:7 
Bristol 12180 Pedicle valve . Zag, 3°08 
Bristol T.1 Pedicle valve . : : Z2S3H0) approx. 2°5 
OUM C652 ~=—- Tortworth pedicle valve . 2:08 I-92 
OUM C654 +‘ May Hill sst.’ pedicle valve 2°50 approx. 2:7 
OUM C5649 H-M-B pedicle valve T72 20% 
OUM C5641 H-M-B brachial valve 

length of trail . : rar a ar6 approx. I-I 


The widths quoted are those of the hingeline, which is by no means always the 
widest part of the valve. 

Discussion. Lamont & Gilbert did not fully describe their varieties, but gave 
good illustrations of the pedicle valves (although no brachial valves were shown), 


STROPHOMENACEAN BRACHIOPODS 321 


and there is no doubt of the shells they had in mind, which are the same as that 
figured by Davidson (1871, pl. XLII, figs. 7, 8). The systematic situation surround- 
ing this species and Brachyprion arenacea has been discussed elsewhere (Cocks 
1967 : 257). 

Lamont & Gilbert’s two ‘ varieties ’ are considered to be one homogeneous species, 
although this shows a remarkable range of variation in many details. They (1945) 
enumerated two differences between the varieties: (1) lobatws was more or less evenly 
curved, whereas geniculatus was geniculate, (11) they had found no specimens of 
lobatus with concave muscle boundary ridges, although they admitted that convex 
forms were to be seen in both varieties. In fact a collection from Gunwick Mill 
shows all variations of geniculation in a single rock band, and a specimen from 
collection T-R-A, OUM C3690/1, shows a lobatus (sensu Lamont & Gilbert) shell 
shape with concave ridges. 

Lamont & Gilbert (1945, p. 668) selected two syntypes, BU 397 and GSM 11461. 
As the first comes from 1030 feet down the Cooperative Society’s borehole at Walsall, 
I propose to select the second specimen as lectotype. This is also the first specimen 
figured by Davidson (1871, pl. XLII, fig. 7) and comes from Gunwick Mill [Grid 
Ref. SO/7430 5152], a locality in which the species occurs up to 5°% and may be 
procured easily today. In addition the Birmingham specimen is poorly preserved 
and incomplete, whereas the lectotype is well preserved and shows the typical 
musculature. 

The species is not common (never more than 5°%) at any locality, but has been 
found in the top part of the Upper Llandovery in beds of C; and C, age at Tortworth, 
May Hill, the Malverns, Ankerdine Hill, Shropshire, Rubery and Walsall, but has 
not so far been recovered outside the Welsh Borderland. 


BELLIMURINA Cooper, 1956 
Bellimurina sp. 
(Pl. 14, figs. 9, 10) 


A single specimen in the British Museum, B 8490, not accurately localized, but 
from ‘Deerhope, Pentland Hills, Scotland,’ may be referred to Bellimurina, a genus 
not so far recorded apart from Cooper’s original description (1956) from the Middle 
Ordovician of America, and a record in the Caradocian of Girvan (Williams 1962). 
The specimen is a natural mould of an exterior of a brachial valve, and the attached 
cardinal area of a pedicle valve. Also on the same slab is a specimen of Eoplecto- 
donta which confirms the late Llandovery age of the specimen. The ornament of 
the leptaeninid is typical of Bellimurina; differentiated parvicostellae, the larger of 
which separate the pattern of broken rugae. The shell is much larger (length 1-83 
cm.) than contemporary Cyphomenoidea, which has a similar ornament, and the 
irregular shell shape and rough geniculation with the frilly lamellae on the gerontic 
trail have not been found in the latter subgenus. 

Thus the stratigraphical range of Bellimurina is significantly increased. 


322 BRL DTS LOW ERS DE UR WAN 


III. ACKNOWLEDGMENTS 


I would lke to thank Mr. J. M. Edmonds and Mr. H. P. Powell of the Oxford 
University Museum (OUM) for the curation of the collections from Shropshire 
which I made whilst at Oxford and for access to those of Dr. A. M. Ziegler from the 
southern Welsh Borderland, with the latter’s ready consent. Thanks also to Dr. 
A. W. A. Rushton of the Geological Survey & Museum (GSM), Mr. A. G. Brighton 
of the Sedgwick Museum, Cambridge (SM) and Dr. M. L. K. Curtis of the Bristol 
City Museum for the loan of other specimens. Most of the material is in the British 
Museum (Natural History) (B and BB). 

I am grateful for valuable advice on aspects of the systematic work from Professor 
Alwyn Williams, and thank also Dr. W. S. McKerrow. I have had useful discussion 
with Dr. V. Havli¢ek, who in addition generously allowed me access to his recent 
(1968) monograph before its publication. 


IV. REFERENCES 


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of Western Tennessee. Bull. Peabody Mus. Nat. Hist., New Haven, 5 : 1-138, pls. 1-34. 

1951. Brachiopods of the Henryhouse Formation (Silurian) of Oklahoma. /. Paleont. 

Tulsa, 25 : 69-96, pls. 15-20. 

Bancrort, B. B. 1949. Welsh Valentian Brachiopods and the STROPHOMENA ANTIQUATA 
group of fossil bvachiopods. 15 pp., 3 pls., privately printed. Mexborough. 

BARRANDE, J. 1848. Uber die Brachiopoden dey Silurischen Schichten von Boehmen. part 2. 

104 pp., pls. 16-23. Vienna. 

1879. Systeme silurien du centve de la Bohéme. \ere partie; volume V. Classe des 

Mollusques. Ordre des Brachiopodes. 226 pp., 153 pls. Prague & Paris. 

Boucot, A. J., JoHnson, J. G., Harper, C. W. & WatmMsLey, V. G. 1966. Silurian brachio 
pods and gastropods of Southern New Brunswick. Bull. geol. Suvv. Can., Ottawa, 140: 
1-145, pls. 1-18. 

CHERNYCHEV, B. B. 10937. The Silurian brachiopods of Mongolia and Tuva (in Russian and 
English). Tvudy Mongolian Comm., 29. Izdatelstvo, Akad. sci. USSR., Moscow, 1-94, 
pls. 1-5. 

Cocxs, L. R. M. 1967. Llandovery stropheodontids from the Welsh Borderland. Palaeon- 

tology, London, 10 : 245-265, pls. 37-309. 

1967a. Depth patterns in Silurian marine communities. MJarine Geol., Amsterdam, 

5: 379-82. 

Cooper, G. A. 1956. Chazyan and related brachiopods. Smithson. Misc. Coll., Washington, 
127 : 1-1245, pls. 1-269. 

Darman, J. W. 1828. Uppstallning och Beskrivning af de i sverige funne Terebratuliter. 
K. Svenska Vetensk. Akad. Hand., Stockholm, for 1827 : 85-155, pls. 1-6. 

Davipson, T. 1847. Observations on some of the Wenlock-limestone Brachiopoda, with 

descriptions of several new species. Lond. geol. Jl., 1 : 52-65, pls. 12, 13. 

1848. Mémoire sur les Brachiopodes du systeme silurien supérieur d’Angleterre. Bul. 

Soc. géol. Fry., Paris, (2) 5 : 309-338, pl. 3. 

1868. On the Upper Silurian Brachiopoda of the Pentland Hills, and of Lesmahagow, in 

Lanarkshire. Tvans. geol. Soc. Glasgow (Pal. Ser.) 1 : 1-24, pls. 1-3. 

1871. British fossil Brachiopoda, 3, Part 7, no. 4, Silurian. Palaeontogy. Soc. |Monogy.], 

London, 24 : 249-397, pls. 38-50. 

1883. Supplement to the fossil Brachiopoda, 5, Part 2, (Silurian). Palaeontogy. Soc. 

(Monogy.|, London, 37 : 135-142, pls. 8-17. 


STROPHOMENACEAN BRACHIOPODS 323 


ForerstE, A. F. 1909. Preliminary notes on Cincinnatian fossils. Bull. sci. labs Denison Univ. 
14 : 209-228, pl. 4. 

GAGEL, C. 1890. Die Brachiopoden der Cambrischen und Silurischen Geschiebe im Diluvium 
der Provinzen Ost-und Westpreussen. Betty. Naturk. Preuss, 1onigsberg, 6 : 1-79, pls. 
I-5. 

Hat, J. & CLARKE, J. M. 1894. An introduction to the study of the Genera of Palaeozoic 
Brachiopoda. Part 2. Palaeontology of New York 8 : (xvi) 1-394, pls. 21-84. Albany. 

HAvLiceK, V. 1963. Familie Leptaenidae (Brachiopoda) im Béhmischen Altpaléozoikum. 

Cas. Ndvodntho Muz. Odd., Prague, 82 : 220-225, pls. 1, 2. 

1968. Brachiopoda of the suborder Strophomenida in Czechoslovakia. Rozpr. Ustr. Ust. 

Geol., Praha, 33 : 1-225, pls. 1-52. 

IMBRIE, J. 1956. Biometrical methods in the study of invertebrate fossils. Bull. Am. Mus. 
nat. Hist., Washington, 108 : 211-246. 

Kinpie, E. M. 1915. Notes on the geology and palaeontology of the Lower Saskatchewan 
River Valley. Bull. geol. Surv. Can. Mus., Ottawa, 21 : 1-25, pls. 1-4. 

Lamont, A. 1947. Gala-Tarannon Beds in the Pentland Hills, near Edinburgh. Geol. Mag., 
Lond., 84 : 193-208, 289-303. 

—— & GILBERT, D. L. F. 1945. Upper Llandovery Brachiopoda from Coneygore Coppice 
and Old Storridge Common, near Alfrick, Worcestershire. Ann. Mag. nat. Hist., London, 
ser. 11, 12 : 641-682, pls. 3-7. 

Linpstr6m, G. 1860. Bidrag till kannedomen om Gotlands Brachiopoder. Ofvers. K. Vetens. 
Akad. Férh., Stockholm, 17 : 337-382, pls. 12, 13. 

MircHeLt, G. H. & Myxura, W. 1962. The geology of the neighbourhood of Edinburgh. 
Mem. geol. Surv. U.K., London, 32 : 1-159, pls. 1-4. 

Murcuison, R. I. 1839. The Silurian svstem founded on geological vesearches in the counties of 
Salop, Hereford, Radnor, Montgomery, Caermarthen, Brecon, Pembroke, Monmouth, Glouces- 
ter, Worcester, and Stafford; with descriptions of the coal fields and overlying formations. 
768 pp., pls. 1-37. London. 

Nixirorova, O. I. & ANDREEVA, O. N. 1961. Stratigraphy of the Ordovician and Silurian 
of the Siberian Platform and its palaeontological basis. (Brachiopods). Biostratigvaphiva 
Palaeozoya Sibirskov Platformy, Leningrad, 1 : 1-412, pls. 1-56. 

Reep, F. R. C. 1917. The Ordovician and Silurian Brachiopoda of the Girvan district. 
Trans. voy. Soc. Edinb., 51 : 795-998, pls. 18-22. 

SHALER, N.S. 1865. List of the Brachiopoda from the island of Anticosti sent by the Museum 
of Comparative Zoology to different institutions in exchange for other specimens, with 
annotations. Bull. Mus. comp. Zool. Havv., Cambridge, 1 : 61-70. 

SoxorsKAyA, A. N. 1954. Strophomenids of the Russian Platform (in Russian). Tvudy 
palaeont. Inst., Moscow, 51 : 1-191, pls. 1-18. 

1g60. Order Strophomenida. In Osnovy Palaeontologu; Mshanki, brakhiopody, vol. ed. 

T. G. SarycHEva, Moscow : 1-324, pls. 1-75. 

SoweErRBy, J. de C. 1823-25. The Mineral Conchology of Great Britain, 5 : 171 pp., pls. 408— 
503. London. 

SPJELDNAES, N. 1957. The middle Ordovician of the Oslo Region, Norway. 8. Brachiopods 
of the Suborder Strophomenida. Norsk geol. Tidssky., Bergen, 37 : 1-214, pls. 1-14. 
TWENHOFEL, W.H. 1928. Geology of AnticostiIsland. Mem. geol. Surv. Brch Can., Ottawa, 

154 : 1-481, pls. 1-60. 

VERNEUIL, P. E. P. de, 1848. Note sur quelques Brachiopodes de Vile de Gothland. Bull. 
Soc. géol. Fr., Paris, (2) 5 : 339-353, pl. 4. 

WAHLENBERG, G. 1821. Petrificata Telluris Svecanae examinata. Nova Acta R. Soc. Scient. 
Upsal., 8 : 1-116, pls. 1-7 (for 1819). 

Wuittarpb, W. F. 1932. The stratigraphy of the Valentian rocks of Shropshire. The Long- 
mynd-Shelve and Breidden outcrops. Q. Jl geol. Soc. Lond., 87 : 859-902, pls. 58-62. 

Wirtiams, A. 1951. Llandovery brachiopods from Wales with special reference to the Llan- 
dovery district. Q. Jl geol. Soc. Lond., 107 : 85~136, pls. 3-8. 


BRI PSE TOW ERSTE UR TAN 


nN 


324 


1953. The classification of the strophomenoid brachiopods. jJ. Wash. Acad. Sci., 43 : 

I-13. 

1953a. North American and European stropheodontids: their morphology and system- 

atics. Mem. geol. Soc. Am., New York, 56 : 1-67, pls. I-12. 

1962. The stratigraphy and brachiopod faunas of the Barr and Lower Ardmillan Series 

(Caradoc) of the Girvan district of S.W. Ayrshire. Mem. geol. Soc. Lond., 3 : 1-267, 

pls. 1-25. 

—— 1963. The Caradocian brachiopod faunas of the Bala District, Merionethshire. Bull. 
By. Mus. nat. Hist. (Geol.), London, 8: 329-471, pls. 1-16. 

—— et al. 1905. Tveatise on Invertebrate Paleontology, Part H, Brachiopoda. Ed. R. C. 
Moore, Univ. Kansas and Geol. Soc. Am.: 1-297, figs. 1-746. 

ZIEGLER, A. M. 1965. Silurian marine communities and their environmental significance. 

Nature, London, 207 : 270-272. 

1966. The Silurian brachiopod Eocoelia hemisphaerica (J. de C. Sowerby) and related 

species. Palaeontology, London, 9 : 523-543, pl. 83, 84. 

——, Cocks, L. R. M. & BamBacn, R. K. 1968. The Composition and Structure of Lower 

Silurian Marine Communities. Lethaia, Oslo, 1: 1-27. 


DESCRIPTIONS OF PLATES 


Unless otherwise stated, all the specimens are coated with ammonium chloride. 
About half the photographs were taken by the author, the remainder by Mr. C. 
Keates. Specimens are in the British Museum (Natural History) (B and BB), 
Oxford University Museum (OUM), Sedgwick Museum, Cambridge (SMA) and 
Geological Survey and Museum (GSM) 


IIL ANID 1B, a 
Pentlandina tartana Bancroft 


Upper Llandovery, Bed D, Pentland Hills, Scotland. Collected by 
Mr. Henderson, now in the Davidson Collection. 
Fics. 1, 2. BB31447. Lectotype. Brachial internal mould and latex cast of it. 2:0. 
Fics. 3, 4. BB 31448. Pedicle internal mould and latex cast of it. 2:0. 
Fics. 5, 6. B8485. Brachial internal mould and latex cast of it. Note pallial sinuses. 
x 2:0. 
Pentlandina parva Bancroft 
Upper Llandovery, The Frolic, Haverfordwest, Pembrokeshire. 


Fic. 7. SMA 30013. Pedicle internal mould. x1-9. 
Fic. 8. SMA 30012. Holotype. Brachial internal mould. x 2:1. 


Pentlandina parabola sp. nov. 
Upper Llandovery, Purple Shale, Domas, Shropshire. Grid Ref. SJ/5936 0062. 
Author’s Collection. 


Fic. 9. OUM C13507. Holotype. Partly exfoliated pedicle valve. x 3:0. 

Fic. 10. OUM C13501. Complete specimen viewed posteriorly, although damaged at the 
apex and laterally. 06-6. 

Fig. 11. OUMCr13512. Brachialinternal mould. x 3:7. 


Upper Llandovery, Purple Shale, Boathouse Coppice, Shropshire. 
Grid Ref. SJ/6205 0398. Author’s Collection. 


Fic. 12, OUMC12856. Pedicle internal mould. x 4:5. 


Pentlandina sp. 


Middle Llandovery, Bog Quartzite, The Bog, Shropshire. Grid Ref. 
SO/3510 9815. Author’s Collection. 


Fig. 13. BB31299. Pedicle internal mould. x 2:0. 


Bull, By. Mus. nat. Hist. (Geol.) 15, 6 PAs 


GEOL. 15, 6. 33 


Pea 2 
Katastrophomena woodlandensis (Reed) 


Middle Llandovery, Woodland Point, Girvan, Ayrshire. Gray Collection. 

Fics. 1,2. B54490. Lectotype. Internal view of pedicle valve and latex cast of it. 1-5. 
Figured Reed 1917, pl. 18, fig. 2r. 

Fic. 3. B73012. Paratype. Figured Reed ror 7, pl. 19, fig. 4. External view of pedicle 
Walye, SK 15, 

Fic. 4. B54478. Paratype. Figured Reed ror 7, pl. 19, fig. 3. Brachial internal mould. 
x15. 

Fic. 5. BB31452. Posterior view of two conjoined valves. 1°5. 

Fics. 6, 7. BB 31426. Brachial internal mould, showing strong convexity and also pallial 
sinuses near the anterior margin. x 1°5. 

Fic. 8. BB 31420. Brachial internal mould which is Meadthyatla tamu ye lane 

Fic. 9. BB 31425. Brachial internal mould. x 1:5. 

Fic. to. BB 31427. Pedical internal mould. Note encrusting epizoon on inner surface. 


X15. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 6 PLATE 2 


PLATE 3 


Katastrophomena woodlandensis geniculata (Williams) 


Upper Llandovery, C, beds, Sefin River, Llandovery, Carmarthenshire. 
Grid Ref. SN/7418 2817. 


Fic. 1. SMA 30008. Holotype. Pedicle internal mould. x 1°5. 
Fic. 2. SMA 30007. Paratype. Brachial internal mould. x1°5. 


Katastrophomena scotica (Bancroft) 


Lower Llandovery, Gasworks Mudstone, opposite entrance to gasworks, 
Haverfordwest, Pembrokeshire. Grid Ref. SM/9588 1533. 


Fic. 3. SMA 32451. Brachial internal mould, figured Bancroft 1949, pl. 1, fig. 5. 1-0. 

Figs. 4-7. SMA 32193. Internal mould, external mould, latex of internal mould and latex 
of external mould of pedicle valve. Paratype. Figured Bancroft 1949, pl. 1, figs. 6,7. 1.5. 
Turnbull Collection. 

Fic. 8. SMA 32194. Lectotype. Pedicle internal mould, figured Bancroft 1949, pl. 1, fig. 4. 
<1°5. Turnbull Collection. 


Lower Llandovery, Gasworks Mudstone, quarry a few yards south of boathouse, 
midway between the springs, The Frolic, Haverfordwest, Pembrokeshire. 
Fic. 9. SMA 30000. Pedicle internal moulds, the right hand one figured Williams 1951, 
Dl WWW B36 wR, 


Pa AWE 3 


Bull. Br. Mus. nat. Hist. (Geol.) 15, © 


PDE ACE 
Katastrophomena penkillensis (Reed) 


Upper Llandovery, Bargany Pond Burn, Girvan Ayrshire. Gray Collection. 


Fic. 1. B73013. Lectotype. Brachial internal mould, figured Reed 1917, pl. 18, fig. 11. 


S105}. 
Fic. 2. BB 31433. Pedicle internal mould. x 2:0. 
Fic. 3. BB 31432. Brachial internal mould. x 2:0. 


Fic. 4. B54480. Brachial external mould, figured Reed 1917, pl. 18, fig. 13. 1-5. 
Fic. 5. B73014. Pedicle internal mould, figured Reed 1917, pl. 18, fig. 12. 2:0. 


Upper Llandovery, Minsterley Formation, Minsterley-Habberley Lane, 
Shropshire. Grid Ref. SJ/3803 0487. Author’s Collection. 


Fic. 6. BB31408. Pedicle internal mould. x 2:2. 


Katastrophomena sp. 
Middle Llandovery, Bog Quartzite, The Bog, Shropshire. Grid Ref. SO/3510 
9815. Author’s Collection. 
Fic. 7. BB31451. Brachial internal mould. x 3:0. 


Upper Llandovery, Venusbank Formation, The Corners, near Betton, Shropshire, 
Grid Ref. SJ/3141 0252. Author’s Collection. 


Fic, 8. BB31407. Pedicle internal mould. X1°5. 


Leptaena martinensis sp. nov. 


Lower Llandovery, Cartlett Mudstones, St. Martin’s Cemetery, Haverfordwest, 
Pembrokeshire. Turnbull Collection. 
lias. g-11. SMA 31865. Internal mould, external mould, and latex cast of external mould 
of pedicle valve. Holotype. x1°5. 
Pic. 12. SMA 31854. Brachial internal mould. x1°5. 
Fic. 13. SMA 31864. Internal mould of both valves, showing part of the brachial interior 
and part of the pedicle exterior. 1°5. 


Bull. Br. Mus. nat. Hist. (Geol.) PLATE 4 


IL NTIS 5 
Leptaena martinensis sp. nov. 


Lower Llandovery, Cartlett Mudstones, St. Martin’s Cemetery, Haverfordwest, 
Pembrokeshire. Turnbull Collection. 


Fics. 1-3. SMA 31859. Internal mould, external mould, and latex cast of external mould 
of pedicle valve of young individual. x 3:0. 


Leptaena haverfordensis Bancroft 


Lower Llandovery, Gasworks Mudstone, opposite entrance to gasworks, 
Haverfordwest, Pembrokeshire. Grid Ref. SM/9588 1533. 


Fic. 4. SMA 32163. Lectotype. Pedicle internal mould figured by Bancroft, 1949, Pl. 1, 
fig. 20. %1°5. Turnbull Collection. 

Fic. 5. BB 31327. Pedicle internal mould. %1°5. Author’s Collection. 

Fics. 6-9. BB 31355. External mould, internal mould, latex of internal mould and latex 
of external mould of pedicle valve. 1-5. C. P. Nuttall Collection. 

Fics. 10, 13. BB 31359. Internal mould and latex of pedicle valve. x1°5. C. P. Nuttall 
Collection. 

Fic. 11. SMA 32162. Pedicle internal mould figured Bancroft 1949, pl. 1, fig. 24. X15. 

Fic. 12. BB 31363. Latex of brachial external mould. 2:0. Author’s Collection. 

Fic. 14. SMA 40512. Pedicle internal mould, figured by Bancroft 1949, pl. 4, figs. 21, 22 
{as L. haverfordensis var. contvacta| 16. Turnbull Collection. 

Fic. 15. SMA 32161. Brachial internal mould figured Bancroft 1949, pl. 1, fig. 23. 1°'5. 


Bull. By. Mus nat. Hist. (Geol.) 15 


ball t 
Datars 
hy 
5 iin 
, acim 


Hedge nr 


PLATE 6 
Leptaena valida Bancroft 


Upper Llandovery, C, beds, Sefin River, Llandovery, Carmarthenshire. 
Grid Ref. SN/7418 2817. O. T. Jones Collection. 

Figs. 1-3. SMA 35690. Holotype. Internal mould, external mould, and latex of external 
mould of pedicle valve. Figured Bancroft 1949, pl. I, fig. 25. %1°5. 

Fic. 4. SMA 35691. Pedicle internal mould. Figured Bancroft 1940, pl. 1, fig. 26 [as 
L. elongata]. 1-5. 

Fic. 5. SMA 35692. Pedicle internal mould. Figured Bancroft 1949, pl. 1, fig. 27 [as 
L. elongata]. X1°5. 

Leptaena urbana Bancroft 


Upper Llandovery, C, beds. O.T. Jones Collection ‘ Locality 27 
NW/E 48, quarry 500 yards NE of Cefn Cerig ’, 
Llandovery, Carmarthenshire. 


Fic. 6. SMA 35693. Lectotype. Pedicle internal mould. Figured Bancroft 1949, pl. 2, 
Gf, It, © $< 1107). 
Fic. 7. SMA 35694. Brachialinternal mould. Figured Bancroft 1949, pl. 2, fig.2. XTI-o. 


Leptaena contermina sp. nov. 


Middle Llandovery, Venusbank Formation, Hope Quarry, Shropshire. 
Grid Ref. SJ/3551 0208. Author’s Collection. 


Fiaes. 8, 11. OUM Co168. Holotype. Pedicle internal mould and latex of it. x 2-0. 

Fics. 9, 12. OUM Cor47. Internal mould and latex of brachial valve. x 2-0. 

Fics. 10, 13. OUMCg9155. Two views of brachial internal mould, the former oblique to 
show details of cardinalia. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, © PLATE 6 


PLATE 7 
Leptaena contermina sp. nov. 


Middle Llandovery, Bog Quartzite, The Bog, Shropshire. 
Grid Ref. SO/3510 9815. Author’s Collection. 


Fic. 1. BB 31280. Pedicle internal mould. 1-5. Note also fragment of Leonaspis sp. 
Fic. 2. BB31289. Pedicle internal mould. x 2:0. 

Fics. 3, 4. OUMCros5o0r1. Brachial internal and external moulds. x 1°5. 

Fic. 5. BB 31283. Brachial external mould. x 2:2. 

Fic. 6. BB 31281. Pedicle internal mould. x1°8. 


Upper Llandovery, Yartleton Beds, May Hill, Gloucestershire. 
Grid Ref. SO/6936 2271. A. M. Ziegler Collection. 


Fics. 7, 8. OUMC2805. Brachial internal mould and latex cast of it. x 1-7. 


Upper Llandovery, Cowleigh Park Beds, Ankerdine Hill, Worcestershire. 
Grid Ref. SO/7376 5696. A. M. Ziegler Collection. 
Pies. 9-11. OUM C7390. Two views of pedicle internal mould and also a latex cast of it. 
X 2:0. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 6 PEATE 7 


PLATE 8 
Leptaena valentia sp. nov. 


Middle Llandovery, Woodland Point, Girvan, Ayrshire, Scotland. 
Gray Collection. 
Fics. 1-3. B 73340. Holotype. Complete shell, figured Reed 1917, pl. 13, fig. 5. 1-5. 
Fics. 4, 5. BB55620. Latex cast and internal mould of pedicle valve. 1-5. 
Fic. 6. BB55718. Latex cast of brachial external. 2-0. 
Fies. 7, 8. BB55688. Latex cast (x 1-6) and internal (x 2-0) of brachial valve. 


Leptaena valentia mullochensis subsp. nov. 


Lower Llandovery, Mulloch Hill, Girvan, Ayrshire, Scotland. 
Gray Collection. 
Fic. 9. B 73384. Holotype. Partly exfoliated pedicle valve, figured Reed 1917, pl 13, 
ft Car Ante 15) 
Fics. 10, 11. B 73379. Internal mould of both valves viewed from either side. x 2:0. 
Fic. 12. BB 31375. Pedicle internal mould. x 2-0. 
Fic. 13. BB31383. Pedicle internal mould. x 2:0. 
Fic. 14. B 73381. Pedicle internal mould. x 2:0. 
Fic. 15. BB 31386. Brachial internal mould. x 2:0. 


PLATE 8 


Bull. By. Mus. nat. Hist. (Geol.) 15, 6 


Fic. 
Fic. 
Fic. 
Fic. 


Fia. 5. 


WN H 


PLATE 9 
Leptaena zeta Lamont, 1947 
Upper Llandovery, Penkill, Girvan, Ayrshire, Scotland. 
Gray Collection. 


B 73355. Lectotype. Pedicle valve, figured Reed 1917, pl. 13, fig. 8. X1°5. 
BB 31302. Pedicle internal mould. x1-8. 
BB 31305. Pedicle internal mould. x 1-8. 
BB 31303. Pedicle internal mould. x1-8. 


Upper Llandovery, Bargany Pond Burn, Girvan, Ayrshire, Scotland 
GSM 4108. Brachial internal mould. x1°8. 


Upper Llandovery, Minsterley Formation, Minsterley-Habberley Lane, Shropshire. 


Fic. 6. 


Grid Ref. SJ/3803 0487. Author’s Collection. 
BB 31468. Brachial internal mould. x 2:2. 


Bull. By. Mus. nat. Hist. (Geol.) 15, 6 PLATE 9 


GEOL. 15, 6. 34 


PLATE to 
Leptaena reedi sp. nov. 


Middle Llandovery, Woodland Point, Girvan, Ayrshire. 
Gray Collection. 


Fic. 1. B 73341. Complete shell, figured Reed 1917, pl. 13, fig. 7. Holotype. x 3-0. 

Fics. 2, 3. B 73345. Pedicle valve. x 3-0. 

Fics. 4, 5. BB31460. External mould of brachial valve and pedicle interarea, and latex 
Cast Of them: x 2:0) 

Fic. 6. BB 31459. Brachial internal. x 3-0. 

Fic. 7. BB 31458. Pedicle internal mould. 3-0. 

Fic. 8. B 73342. Brachialinternal. x 2-0. 

Fics. 9-12. BB 31457. Two views each of pedicle internal mould and latex cast of it. Note 
close association with L. valentia. 2-0. 

Fic. 13. BB31461. Brachial external mould. 3:0. 

Fic. 14. B 73346. Complete shell. 3:0. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, 6 IRL NADIE, ae (0) 


Pi Agr ear 
Leptaena ziegleri sp. nov. 


Upper Llandovery, Wych Beds, Malvern Hills, Herefordshire. 
Grid Ref. SO/7612 3811. A.M. Ziegler Collection. 


Fics. 1, 2. OUM C4146. Pedicle internal mould and latex of it. Holotype. x 3:3. 
Fics. 3-5. OUM C4136. Internal mould, latex of it and external mould of brachial valve. 
MK BB. 


Leptaena quadrata Bancroft 


Upper Llandovery. O. T. Jones locality ‘Loc. K, below path SW of Uzmaston’, 
The Frolic, near Haverfordwest, Pembrokeshire. 


Fics. 6-8. SMA 32437. Internal mould, external mould, and latex of external mould of 
pedicle valve. Lectotype. Figured Bancroft 1949 pl. 1, fig. 28. x 3:0. 

Fic. 9. SMA 32438. Brachial internal mould, figured Bancroft 1949, pl. 1, fig. 29. 3:0. 

Fic. 10. SMA 32439. Pedicle internal mould, figured Bancroft 1949, pl. 1, fig. 30. ™ 3:5. 


Bull. Br. Mus. nat. Hist. (Geol.) 15, © ID NARA ert 


PLATE 12 
Leptaena purpurea sp. nov. 


Upper Llandovery, Purple Shale, Shropshire, various localities. 
Collected W. F. Whittard and author. 

Fic. 1. BB 31465. Holotype. Pedicle internal mould, also pedicle internal mould of 
Glassia obovata (J. de C. Sowerby). Domas. Grid Ref. SJ/5936 0062. x 2°5. 

Fic. 2. BB31463. Pedicle internal mould. Gippols Dingle. Grid Ref. SO/5727 9937. 
x 2:5. 

Fic. 3. BB 31466. Brachial valve, also Aegivia grayi (Davidson). Hughley. Grid Ref. 
SO/5639 9809. x 3:0. 

Fic. 4. OUMC12062. Pedicle internal mould. Onny River. Grid Ref. S/O4260 8532. 
X 3:0. 

Fic. 5. BB 31464. Pedicle internal mould. Hughley. Grid Ref. SO/56379795. x2°5. 


Leptaena ci. purpurea sp. nov. 


Upper Llandovery, Damery Beds, eastern bank of railway cutting, immediately 
north of road bridge, Charfield Station, Gloucestershire. 
M. L. K. Curtis Collection. 


Fic. 6. Bristol University Museum 12101. Pedicle internal mould. x 1°8. 


Leptaena sp. 
Upper Llandovery, Purple Shale, ‘ Harley ’, Shropshire. 
W. F. Whittard Collection. 
Fics. 7, 8. BB31467. Complete shell viewed dorsally (x 1-6) and posteriorly (x 2:5). 


Cyphomena (Cyphomenoidea) wisgoriensis (Lamont & Gilbert, 1945) 
Upper Llandovery, Wyche Beds, Malvern Hills, Herefordshire. 
Grid Ref. SO/7430 5152. A. M. Ziegler Collection. 


Fic. 9. OUM C5638. Pedicle internal mould. x 1-7. 

Fic. 10. OUM C5631.